**Joint Mobility Protection during the Developmental Age among Free Climbing Practitioners: A Pilot Study**

**Ludovica Gasbarro 1,**†**, Elvira Padua 1,**† **, Virginia Tancredi 2, Giuseppe Annino 2, Michela Montorsi 1,\* , Grazia Maugeri 3,\* and Agata Grazia D'Amico <sup>1</sup>**


Received: 5 September 2019; Accepted: 10 February 2020; Published: 17 February 2020

**Abstract:** Sport-climbing popularity increased intensely over the past years. Particularly, children's and adolescents' interest therein is constantly growing. Despite a large effort in preventing injuries and muscle overloads, a fine-tuned training for each sensitive phase of child development is still needed. The objective of the study was to evaluate an innovative training program aimed at the preservation of joint mobility during the developmental age. This article relies on the results of a steady training program allowing to retain joints integrity among the practice of sport climbing in children. Joint mobility changes have been monitored before and after a one-year training program in fifteen subjects aged between 8 and 18 years. Subjects were divided into three groups depending on age (Turgor Secundus, Proceritas Secunda and Turgor Tertius). The motor tests administered were the sit-and-reach test, coxo-femoral mobility test and scapula–humeral mobility test. Our results showed that one-year training improved joint mobility at each analyzed phase, suggesting that this training program could improve mobility and flexibility. Given the importance of joint mobility preservation for discipline-related injuries prevention and eventually recovering, it is essential to provide a specific training program as a route to approach sport climbing, and even more importantly, at an early age. This work represents a preliminary study in order to demonstrate both efficacy on the joint mobility and the requirement of our playful work to support the global sport-climbing workout.

**Keywords:** joint mobility; development phases; sport climbing; stretching

#### **1. Introduction**

In the last decades, rock climbing has become a popular sport among adults, adolescents and children, also since it being included in the 2018 Summer Olympic Youth Games in Buenos Aires and in the Summer Olympic program of the 2020 Games in Tokyo [1,2]. In using only their bare hands and climbing shoes to perform a range of hand and foot holds, athletes climb vertical walls in three disciplines: Speed, with two climbers simultaneously climbing a route on a 15 m wall; Bouldering, with athletes performing in a given time a number of fixed routes on a 4m wall; and Lead, with athletes climbing in a given time a 15 m wall [3]. It is possible to practice it not only outdoor, as now there also are indoor structures; so, this sport is becoming widespread in adults and adolescents, too.

Rock climbing has several benefits on both physical fitness and mental care. In fact, this sport improves strength and endurance [4,5]. A recent study [6] has demonstrated that rock climbing significantly improves muscle power, ability to produce a maximal force in a short time, muscle endurance and skills to perform a continuous muscle work for a long time. This kind of sport also has beneficial effects on depressive disorders due to the positive effect on cognitive control of the physical activity connected to high levels of coordination [7]. It has been demonstrated that only a single rock-climbing session may have a positive effect in major depressive disorder [8].

Due to the increased popularity, the average age of rock climbers is decreasing, and more and more young athletes win medals. Unfortunately, the increased number of young rock climbers involves a major risk of an injury in the developmental age [9].

During climbing very small parts of the hands and feet are in contact with the climbing surface [10–12] and climbers have to support and/or lift their bodies by combining a variety of finger grips with balanced, complex vertical and lateral movements and position holds [13,14]. To guarantee grip and stability, specialized smooth climbing footwear with a sticky rubber sole are used. Although climbing shoes should fit snug without pain, the climbers tend to use smaller sizes, which could cause injuries or foot deformation [15].

Physical activity is essential to maintain good health and guarantee a better quality of life. The major sport-related benefits involve not only the body but also the mind. In fact, physical activity improves motor and cognitive skills, reduces risk for obesity, exerts positive effects on blood pressure and lipidemia, as well as decreasing the risk of depression and other mental disorders [16,17]. However, incorrect or excessive training may lead to adverse effects, including musculoskeletal injuries, recently described in young soccer players, as well as social–occupational dysfunction [18,19]. In particular, in rock climbing the articulations are very solicited and the scientific literature reports injuries in fingers or in shoulders [15,20]. In particular, Garcia et al. [21] examined hands and fingers of young climbers versus a control group of non-climbers and they showed a non-physiological development of fingers. Similarly, another study [22] showed differences in the static scapular position between rock climbers and a control group.

In particularly the developmental age there is a major risk of sprains, strains and fractures with chronicle injuries at the upper extremity and acute injuries at the lower extremity [23]. A survey among rock climbers [24] reports 90% upper extremity injuries, and among these the most common are fingers followed by shoulder/arm and elbow/forearm.

Rock climbing is positively related to increased bone mineral content, weight and mass body [15]. However, for climbers a low body mass index is an ideal anthropometric requirement. Therefore, they perform a restricted diet to maintain a low body weight, by inducing a negative effect on their health and in particular on their bones [25,26]. Moreover, the stresses associated with rock climbing may have the potential to create scapula–humeral or coxo–femoral injuries [22].

Despite the increase in rock-climbing practices and the consequent increase in studies on the benefits or injuries of climbing, little data are available on adolescents.

To envision the development of effective preventative measures for preserving the joint mobility and health of youth practitioners, the aim of this preliminary study was to evaluate the effects of a specific pre-training rock climbing program to be administered to athletes according to their developmental status.

Therefore, in this preliminary study we evaluated an innovative training program to preserve joint mobility during the developmental age. Children were subjected to a steady training program in order to retain joint integrity and to avoid climbing-associated injuries.

#### **2. Materials and Methods**

#### *2.1. Subjects*

Fifteen subjects aged between 8 and 18 years, working out regularly in sport climbing and joint mobility, were divided into 3 groups consisting of 5 athletes each according to their ages. Turgor Secundus (3 boys and 2 girls; aged between 8 and 10), Proceritas Secunda (2 boys and 3 girls; aged between 12 and 14) and Turgor Tertius (2 boys and 3 girls; aged between 15 and 18).

Table 1 reports the anthropometric characteristics of the athletes, divided in subgroups according to their developmental phase.

**Table 1.** Characteristics of participants recruited to conduct the present study expressed as mean fold change ± SEM.


This study received the consence by the Institutional Research Board of the University San Raffaele of Rome, Italy and all subjects' legal tutors gave written informed consent in respecting the ethical principles of the Declaration of Helsinki. All participants were novices regarding climbing experience.

#### *2.2. Methodology*

Knowledge of the main physiological changes and the sensitive phases of development is fundamental for the educator, as on the basis of this information he can develop a program suitable for the child's needs. The sensitive phases of development are periods of growth in which the child will be predisposed to increase some motor skills rather than others. Furthermore, the differential growing of the bones, nervous system and muscles in the different evolutionary phases must be taken into consideration in the programming to avoid injuries and the onset of paramorphism.

Our study was conducted for 12 months, and during this experimental period the climbing training program was carried out according to the coach's training plan. Children worked out twice a week for 90 min divided as follow: 15 min for stretching, 20 min for specific training to improve joint mobility and 55 min for climbing.

Joint mobility variation was assessed over a one-year training period. All the measurements were performed at baseline (time 0; start measurement) and repeated at the end of the training period (time 1; after 12 months) in order to evaluate scapula–humeral and coxo–femoral joint mobility and spine flexibility. The measures recorded in time 0 were considered our control data and the measures obtained at the end of training program were compared to data recorded in time 0 in order to calculate the improvement of joint mobility for each group.

Tests have been performed as follows:

Sit-and-reach test: Participants sat on the floor with legs extended, backs straight and feet resting on a cube with a graduated wooden board above it. The participants are asked to slide their hands above the wooden board, keeping the knee extended [27].

Hip joint mobility: Participants are sitting with their back against the wall, slowly reaching the maximum opening of their hips. The measurement is then taken between the inner ankles [28].

Scapulo–humeral mobility test (measurement of shoulder mobility): Participants are in an upright position, holding a stick, bringing the arms outstretched behind the trunk and reaching the starting position without bending the arms. Then, the minimum distance between the hands while the subject is holding the stick was measured [29].

#### *2.3. Training Regime*

Participants of the three experimental groups underwent a specific training program 2 times/week, performing 15 min of general warm-up before training. The specific training program for each phase was done for 20 min before rock climbing.

According to each phase, the following training methods were proposed in order to improve joint mobility.

The Turgor Secundus phase: Obstacle course on wall bars (Figure 1) to preserve a good degree of flexibility and to practice the typical positions of sport climbing:

Exercise 1: The aim was to start from the left side of the wall bar and moving sideways to pass over, under and through some obstacles, following a predetermined path, without falling (Figure 1).

**Figure 1.** Children performing exercises starting from the left side of the wall bar and moving sideways to pass over.

Exercise 2: The game of spiders and crabs: half of the children have to positioning themselves in a line, keeping their arms and legs outstretched, forming a large arch. The crabs will have to come through it (Figure 2).

**Figure 2.** Overview of spider and crab positions.

The Proceritas Secunda phase: Mobilization of the spine (Figures 3 and 4a,b) and the tibio–tarsic joint (Figure 5):

Exercise 1: Hamstring stretch involving two subjects (A and B) that have to sit back-to-back on the floor with their legs extended forward. Subject A is stretching back by abducting his/her arms upwards slightly pressing its weight, and simultaneously subject B reaches for his/her toes. The position has to be kept constant for 4–5 s, after which this exercise is repeated but with the subjects changing their roles (Figure 3).

**Figure 3.** Final position of the spine mobilization exercise.

Exercise 2: The subjects sit up tall in the straddle position feet-to-feet, with straightened legs, and holding a ball in their hands (Figure 4a). They slowly lean down on the back, closing their legs and curling the pelvis inward until their toes touch the ball behind their heads, and then back to the starting position (Figure 4b).

**Figure 4.** (**a**) Starting position of the mobilization of the spine and coxo–femoral joint exercises. (**b**) Ending position of the mobilization of the spine and coxo-femoral joint exercises.

Exercise 3: In single foot support, rotate the rope forward without jumping. After rotating the rope forward, to pass the rope beyond the foot, flex the foot and then extend it. Do the same with the other foot (Figure 5).

**Figure 5.** Flex foot and rope locked by the foot.

Turgor Tertius phase: Mobility exercises for the fingers (Figure 6), coxo–femoral (Figure 7) and tibio–tarsic joints (Figure 8):

Exercise 1: Starting with a hand fully opened; perform four closing finger movements, through which both the metacarpophalangeal and the interphalangeal joints will be stimulated (Figure 6).

**Figure 6.** Mobility exercises for fingers from starting to ending positions.

Exercise 2: The subject is crouched down, the feet are in a wide stance with the toes turned out, the back outstretched, the heels on the ground and the elbows slightly pushing the knees outwards. Then, small rotations of the ankles are made first in one direction and then in the other (Figure 7).

**Figure 7.** Squat position for mobilization of the coxo–femoral joint.

Exercise 3: Four different types of gaits are proposed. First, toe walking with raised arms. Second, heel walking with raised arms. Third, foot rolling forward. Lastly, feet supination and pronation walking forward (Figure 8A–D).

**Figure 8.** (**A**) Toe walking with raised arms; (**B**) foot rolling forward; (**C**) heel walking with raised arms; (**D**) feet supination and pronation walking forward.

#### *2.4. Statistical Analysis*

Data collected at baseline (pre-training) and after (post-training) the one-year experimental period are presented as the mean ± SD. The assumption of normality was verified by means of the Kolmogorov–Smirnov test. Then, for each subgroup a paired *t*-student test was used to ascertain differences between pre-training and post-training data. Throughout the study, the level of significance was set at *p* ≤ 0.05. Statistical analysis was conducted using GraphPad Prism version 6.

#### **3. Results**

Athletes have carried out the proposed activities for the entire duration of the study over and above the regular workout, with the exception of a female belonging to the group Proceritas Secunda who interrupted the training program for one and a half months. However, data from subjects who dropped out were used for preliminary comparisons. All groups considered in our study have shown an improvement in joint mobility (Table 2). However, differences in training response among the considered phases have been identified.

**Table 2.** Percentage of improvement in flexibility in the different phases expressed as mean fold change ± SD.


Proceritas Secunda showed a positive response in coxo–femoral mobility and lower vertebral column flexibility 12 months after the start of the training program (Figures 9 and 10), whereas scapula–humeral mobility did not report benefits after joint-specific training (Figure 11). On the other hand, scapula–humeral mobility remarkably improves in the Turgor Tertius phase when compared to both Turgor Secundus and Proceritas Secunda (Figure 11). Indeed, this is consistent with the normal development of the shoulder joint that tends to complement the most advanced evolutionary phases. However, this does not apply to the other two phases (Figure 11). The Turgor Tertius group have also recorded an improvement in spine flexibility as reported in Figure 10.

Regarding Proceritas Secunda, we further compared two 14-year-old subjects (Figure 12). Athlete A has completed his/her training, whereas Athlete B has totally interrupted the workout for one and a half months. The latter has been previously excluded from the overall analysis. It is noteworthy that we clearly identified a remarkable impairment in terms of mobility and flexibility as a result of the training discontinuation of Athlete B.

**Figure 9.** Coxo–femoral mobility test. The results are represented in bar graphs as the mean ± SD of the different phases considered (Turgor Secundus, Proceritas Secunda and Turgor Tertius).

**Figure 11.** Scapulo–humeral mobility test. The results are represented in bar graphs as the mean ± SD of the different phases considered (Turgor Secundus, Proceritas Secunda and Turgor Tertius).

**Figure 12.** Comparison between the percentage mean variations of two athletes: Athlete A has completed the training, while Athlete B has totally interrupted the workout for one and a half months.

#### **4. Discussion**

This work represents a preliminary study in order to demonstrate both the efficacy on joint mobility and the requirement of our playful work, to support the global sport-climbing workout. Indeed, the increased interest in rock climbing practices creates the need to know all the possible sport-related injuries in order to prevent and treat them. Hence, the importance to study the main joints involved in climbing and that are at risk of injuries, such as joints of the hand and fingers, shoulders, the hip and ankles, in order to develop a preparation workout suitable for the discipline.

Since sport climbing does not need specific anthropometrical characteristic, and for this reason it can be practiced by everyone [30], a specific training program in this sport can improve one's strength and resistance; essential skills that would allow to carry out increasingly difficult passages. In fact, climbers perform movements that require an isometric effort, resulting in an enhanced muscle tone to obtain a strong and harmonious body. Moreover, although it is not an aerobic discipline, it develops a good cardiovascular training; this is also due to the adrenaline that develops while climbing [31].

Because of a child's incomplete maturation of both bone and muscular structures, and the laxity of ligaments, early and specific training would reasonably provide extensive room for improvement. We have proposed a playful training workout as a mobility workout in the first sensitive stages.

In the present work, we have conducted a preliminary study in an attempt to prove that a specific training program is fundamental for mobility and flexibility improvement. Participants enrolled for our study were novices regarding climbing experience and they worked out twice a week for 90 min in agreement with the coach's training plan for 12 months.

Although the reported data did not reach statistical significance, we have recorded an improvement in joint mobility after the playful training program. However, not all the recorded ameliorations were statistically significant. This might be due to external factors affecting joint mobility, such as anatomical and physiological differences among subjects. However, this can be also ascribable to the low sample size. The latter stems from the direct correlation between the standard deviation value and the sample size.

Moreover, by comparing continuous and discontinuous training between two athletes, we have suggested the importance of early and constant training (Figure 12). Indeed, the suspension of a joint-specific workout can lead to a blockage or even a regression of the subject's abilities. Thus, injuries require prompt treatment in order to avoid transient and permanent physical impairment.

Even if the study was conducted on a low number of subjects, this represent a starting project in order to develop a specific training program for each developmental phase.

#### **5. Conclusions**

The recent proliferation of indoor climbing gyms and well-protected sport climbing areas have made sport climbing accessible to everyone. Neither an age group nor a pre-existing medical condition serves as a contraindication for sport climbing in the first instance. Sport climbing is an engaging mental and physical activity that contributes to an increase in muscle mass and strength, dynamic balance, and other health benefits. However, in line with any exercise prescription, guidelines for sport-specific participation are desirable. Taking into account what was shown in this preliminary study, early and constant joint-mobility training that start from the early stages of the developmental age is fundamental.

In conclusion, we suggest that joint-mobility exercises from the early stages of development will allow children to move harmoniously, even on the climbing walls.

**Author Contributions:** Conceptualization, L.G. and A.G.D.; methodology, L.G.; validation, E.P. and G.A.; formal analysis, M.M. and V.T.; investigation, L.G.; data curation, A.G.D.; statistical analysis, G.M. and A.G.D.; writing—original draft preparation, M.M., A.G.D. and E.P.; writing—review and editing, M.M.; G.M. and V.T.; supervision, A.G.D. All authors read and approved the final manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**




© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## *Article* **Cognitive and Physical Activity-Related Aspects of Children Associated to the Performance of the Crunning Movement**

**Ewan Thomas 1,\* , Marianna Alesi <sup>1</sup> , Garden Tabacchi <sup>1</sup> , Carlos Marques da Silva <sup>2</sup> , David J. Sturm <sup>3</sup> , Fatma Ne¸se ¸Sahin 4, Özkan Güler 4, Manuel Gómez-López <sup>5</sup> , Simona Pajaujiene <sup>6</sup> , Michele Basile 7, Ante Rada 8, Antonio Palma <sup>1</sup> and Antonino Bianco <sup>1</sup>**


**Abstract:** The aim of this investigation was to identify possible related factors associated to the performance of the crunning test in European children and adolescents. A total number of 559 children and adolescents (age range 6–14 years) of which 308 boys (55.1%) and 251 girls (44.9%), from seven European countries, were screened. A questionnaire concerning demographic and personal life-related factors and a cognitive assessment were performed. A regression analysis was conducted with the performance measures of the crunning movement. T-tests and ANCOVA were used to analyze sub-group differences. Boys have greater crunning performance values compared to girls (5.55 s vs. 7.06 s, *p* < 0.001) and older children perform better than younger ones (R2 −0.23; *p* < 0.001). Children with healthy and active habits (exercising or spending time with family members vs. reading or surfing the internet) performed better in the test. Children engaged in team sports had better crunning performances compared to those engaged in individual sports (6.01 s vs. 6.66 s, *p* = 0.0166). No significant association was found regarding cognitive-related aspects in either children engaged in team or individual sports and the crunning performance. Older and male children performed better in the crunning test than younger and female children. Physical activity-related aspects of children's life are associated with crunning movement performance. No association was found between higher cognitive performance and the crunning test results.

**Keywords:** crunning; socio-demographic; cognitive; fitness-tests

#### **1. Introduction**

Physical fitness (PF) during childhood and adolescence has been deeply investigated [1–3]. It has been recognized that PF is an important health-related factor, which may predict health status in adulthood, and which may also help physical and cognitive development [1,4–6]. Inverse associations have been found between PF and cardiovascular disease, metabolic risk factors and adiposity, which overall suggest positive health-related

**Citation:** Thomas, E.; Alesi, M.; Tabacchi, G.; Silva, C.M.d.; Sturm, D.J.; ¸Sahin, F.N.; Güler, Ö.; Gómez-López, M.; Pajaujiene, S.; Basile, M.; et al. Cognitive and Physical Activity-Related Aspects of Children Associated to the Performance of the Crunning Movement. *J. Funct. Morphol. Kinesiol.* **2021**, *6*, 9. https://doi.org/10.3390/ jfmk6010009

Received: 16 December 2020 Accepted: 13 January 2021 Published: 17 January 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

aspects [5,7,8]. A recent review by Donnelly et al. [4], investigating the effects of PF on cognition, learning and brain structure and function in children aged 6–13 years old, found a general positive association regarding cognition and brain structure and function. However, the study failed to identify a specific set of activity parameters which may better promote the abovementioned aspects. However, despite different evidence existing regarding a positive association between physical activity (PA) and academic achievements [9], there are still inconsistencies regarding aspects of PA and cognitive function [4].

In order to promote the level of PF through PA in adulthood, it is important to adequately modify lifestyle and behaviours in childhood and adolescence [10,11]. Different investigations have suggested that children and adolescents who did not regularly practice PA are more prone to develop unhealthy habits as smoking or drinking alcohol [12,13], which would inevitably decrease PF. In addition, such aspects have also been linked to the familial socio-economic status, parental education and food habits [12,13]. Therefore, since lifestyle and familial education are important factors which influence both physical and psychological development of children and adolescence, these may be considered as important predictors of PF and health outcomes [14].

In order to quantify the levels of PF, a large body of scientific evidence exists which takes into account specific age ranges and genders [1,15–18], demographic characteristics [19–21] or more specific sub-populations [22,23]. Each investigation has evaluated different aspects related to PF, such as aerobic activity, strength, power, speed, coordination, flexibility, agility and other abilities, including for each of these, one or more field or laboratory tests to appropriately discriminate such abilities.

Despite the large number of fitness tests and physical evaluation batteries available, performance values or predictors of the crunning movement, a specific type of locomotion which combines running and crawling, are scarce. Patrick et al. [24] evaluated the inter-limb coordination during crawling in infants and adults, suggesting that a great involvement of coordination by the central nervous systems is required for quadrupedal locomotion. Other two investigations have included specific crawling exercises, within a fitness battery, to improve PF in a military environment [25,26]. The results of the studies underline that the military personnel increased the efficacy of different abilities, such as coordination, agility, speed, and power, following such interventions. Another investigation tried to determine a link between the Illinois agility test, which evaluates agility, and the crunning test. The results indicate a moderate correlation (r = 0.45) between the two tests [27], suggesting that a certain amount of agility is required to perform the crunning movement. In an attempt to understand if the crunning locomotion could provide further information than those offered from already known fitness tests, we included the crunning test in a previously discussed project [15]. This project, namely, the Enriched Sport Activity (ESA) program, was a physical activity intervention with the aim to improve fitness of children and adolescents across Europe by including cognitively enriched stimuli within specific warm-ups, prior to a structured physical activity [15]. However, such tests, together with the Leger shuttle run for aerobic assessment [28], were the only tests not influenced by the ESA intervention.

In order to clarify the characteristics of the crunning movement, this investigation will aim to identify lifestyle, physical activity and cognitive aspects associated with the results of this particular type of locomotion.

#### **2. Materials and Methods**

#### *2.1. Participants*

The sample was composed of 589 children of ages ranging from 6 to 14 years (aged 10.25 ± 1.76 years and 9.98 ± 1.87 years) of which 308 boys (55.1%, age 9.1 ± 1.3 years; weight, 34.9 ± 9.5 kg; height, 139.0 ± 10.4 cm) and 251 girls (44.9%, 10.2 ± 1.8 years; 39.4 ± 11.1 kg; 144.8 ± 14.3 cm), from 7 European countries (Italy, *n* = 164 of which 92 boys and 72 girls; Germany, *n* = 64 of which 41 boys and 23 girls; Portugal, *n* = 111 boys; Spain, *n* = 37 of which 17 boys and 20 girls; Lithuania, *n* = 85 of which 53 boys and 32 girls; Croatia, *n* = 50 of which 25 boys and 25 girls; and Turkey, *n* = 78 girls) within the ESA Program, an evidence-based exercise program cofounded by the Erasmus + Program of the European Union (Key action: Sport-579661-EPP-1-2016-2-IT-SPO-SCP).

Criteria for including participants were the following: 1. Able to perform the required tests; 2. Absence of a diagnosis of intellectual disability, visual or neurological impairments; 3. Absence of a diagnosis of other neurodevelopmental disorders. All children were recruited within a school or sport center. Before the inclusion of the children in the ESA program, a parent or legal representative of each child signed a declaration of informed consent. The study was conducted in accordance with the Helsinki Declaration (Hong Kong revision, September 1989) and the European Union recommendations for Good Clinical Practice (document 111/3976/88, July 1990). The study was approved with permission from the Lithuanian Sports University's Research Ethics Committee in Social Sciences with approval No 579661-EPP-1-2016-2-IT-SPO-SCP (2018-02-05).

#### *2.2. Study Design*

The ESA Program aimed to improve children's motor skills and executive functions through sport activities enriched by cognitive stimuli to enhance inhibitory control, working memory and shifting.

Detailed description of the study design and the ESA Program can be found elsewhere, describing both the cognitive tests and their administration and motor components, as well as the full description of the crunning test and administration procedures within the project [15,29].

#### *2.3. Intervention Procedure and Assessment Tools*

Each ESA trainer underwent a training procedure before the start of the intervention, in order to adopt a standardized procedure. The procedure was shared across the participating countries. This can be also found on a dedicated YouTube channel (ESA Program). Therefore, all testing procedures were performed in the same way and order. At the beginning of the project, each participant underwent a cognitive examination [29] and a physical evaluation [15], which were repeated at the end of the intervention. Before the start of the ESA training program, each participant also underwent a psychological test battery (ESA PTB, a 32 item questionnaire which includes questions regarding personal information, lifestyle-related factors and school-associated information), which was administered on two different occasions prior to the inclusion of the participants in the ESA program. On the first day, the participants underwent a cognitive assessment which lasted around 1 h [29]. On the second day, a questionnaire was administered, which included questions related to habits, family, recreational and social aspects. We retrospectively evaluated the predicting factors of the crunning performance through these personal aspects.

The crunning performance, measured as the time in seconds needed to perform the test (10 m distance), was the dependent variable collected through the crunning test, included in the ESA fitness battery. This battery is composed of six fitness tests (standing broad jump, seated medicine ball throw, 20 m shuttle run test, 30 m sprint, Illinois test and the crunning test) to assess different skill-related components at once [30], but for the purpose of the present paper, only the outcomes of the crunning test have been considered [15]. Low values in the test measure indicate better performance.

For the purpose of this study, gender and age were treated as covariates, while a number of predictors were taken into account. These predictors included sport-related aspects, spare time-related aspects and cognitive or neuropsychological aspects.

Each aspect is discussed below.

(a) Sport-related aspects: Sport type (individual/team and exercise intensity) and sport frequency.

Individual/team sport type classification was manually distinguished by the authors on the basis of the sport practiced. The American Heart Association classification for sport was adopted [31] for grouping the activities in relation to cardiovascular function. These are divided by static and dynamic activities, and each is stratified according to exercise intensity, categorized as low, moderate or high. Current sport frequency and past sport frequency were measured in hours per week and relevant data were collected through a dedicated section of the ESA PTB.

(b) Spare time-related aspects (frequencies in h/week): Aspects regarding time spent with parents and siblings, reading, going to the cinema, theatre or museums, surfing the internet, playing with electronic games, going out with friends, going to the gym, going to the park or shopping were evaluated. All these items were collected through a dedicated section of the ESA PTB.

(c) Cognitive/neuropsychological variables: School marks (National language, Maths, Anthropology and History, Geography, Physical education, Foreign language), inhibitory control, working memory, shifting of attention. The ESA PTB was used to collect the school mark items. The other items' assessment was performed through the neuropsychological tests derived by the Inquisit Lab platform (Inquisit 6 (for Windows version 6.1). 2020. Retrieved from https://www.millisecond.com): the Color Word Stroop (CWS) task for the inhibitory control, measured by the time needed to select the right color within the stroop test; the Digit Span Test (DST) for working memory, measured by the number of recalled digits in an exact order and in a reversed order; and the Trail Making Test (TMT) for shifting of attention, measured by error number and execution time. For further details regarding the cognitive test administration, please refer to Gentile et al. [29].

#### *2.4. Statistical Analysis*

Data are presented as means and standard deviations. The Student's t-test was used to assess differences in the crunning test for each variable (i.e., gender, sport type). To estimate differences in the crunning performance by country, age range and sport type, the ANCOVA test was performed. Age and gender were used as covariates for all analysis.

Linear regression analyses were performed to evaluate correlations between the crunning test and sport frequency, spare time-related aspects, cognitive/neuropsychological aspects. Statistical significance was set for *p* < 0.05. All estimates were adjusted for gender and age. The software STATA/MP 12.1 (StataCorp. 2011. Stata Statistical Software: Release 12. College Station, TX, USA: StataCorp LP.) was used for the statistical analysis.

#### **3. Results**

#### *3.1. Gender and Age*

Mean time to perform the crunning test was 6.25 s (SD 2.416, *n.* = 589). Better crunning performances were observed for males compared to females (independently from age) and for older compared to younger children (independently from gender) (Table 1). The regression coefficient for age was −0.23 (SE 0.051, *p* = 0.000, *n* = 589).

**Table 1.** Differences in the crunning test performances by gender and age range.


SD: Standard deviation; Tot: Total number; <sup>a</sup> Estimated through paired Student's *t*-test. <sup>b</sup> Estimated through ANCOVA. All estimates were adjusted for gender and age.

#### *3.2. Demographic Factors*

Table 2 shows the differences in the crunning movement performances by demographic and SES factors. Similar characteristics across participants for each county were observed (Italy, 8.5 ± 1 years; 34.3 ± 9.8 kg; 135.0 ± 9.8 cm; boys, 8.4 ± 1 years; 33.9 ± 9.7 kg; 135.3 ± 9.7 cm and girls, 8.6 ± 1.1 years; 34.8 ± 10.1 kg; 134.7 ± 10 cm; Germany, 8.9 ± 0.8 years; 37.6 ± 9.9 kg; 137.8 ± 7.5 cm; boys, 9.0 ± 0.8 years; 37.6 ± 8.4 kg; 138.6 ± 7.3 cm and girls, 8.7 ± 0.7 years; 37.4 ± 12.7 kg; 136.3 ± 7.9 cm; Portugal, boys, 10.9 ± 1.7 years; 139.1 ± 15.3 cm; 39.4 ± 9.3 kg; Spain, 10.5 ± 1.0 years; 142.7 ± 20.4 cm; 45.1 ± 23.1 kg; boys, 10.4 ± 0.9 years; 145.8 ± 14.1 cm; 43.2 ± 12.4 kg and girls, 10.4 ± 1.0 years; 144.7 ± 13.2 cm; 40.2 ± 10.4 kg; Lithuania, 9.9 ± 1.13 years; 35.7 ± 8.0 kg; 144.0 ± 9.0 cm, boys 9.9 ± 1.19 years; 36.4 ± 8.9 kg; 144.0 ± 9.0 cm and girls 10.1 ± 1.02 years; 34.6 ± 5.8 kg; 142.0 ± 11.0 cm; Croatia 9.4 ± 0.5 years; 35.0 ± 8.2 kg; 138.3 ± 7.6 cm; boys, 9.7 ± 0.5 years; 36.5 ± 7.6 kg; 140.7 ± 7.4 cm and girls, 9.3 ± 0.5 years; 34.7 ± 8.3 kg; 137.8 ± 7.6 cm; and Turkey, girls, 10.8 ± 1.8 years; 134.9 ± 12.7 cm; 45.3 ± 10.9 kg). Significant differences in the crunning movement were found across countries.

**Table 2.** Differences in crunning test performances by country and socio-economic status.


SD: Standard deviation; <sup>a</sup> Estimated through ANCOVA. All estimates were adjusted for gender and age.

#### *3.3. Sport-Related Aspects*

Among the sport-related aspects, the following were found to be associated to better performances: team sport type, with children practicing team sports performing better than those practicing individual sports (h/week) (Table 3).

**Table 3.** Differences in crunning test performances by sport-related aspects.


SD: Standard deviation; SE: Standard error; <sup>a</sup> Estimated through paired Student's *t*-test. <sup>b</sup> Estimated through linear regression analysis. \* Five sport categories were included, according to the American Heart Association classification adopted.

No differences were found across different sports, current sport frequency, sport type (based on the American Heart Association classification (impact)).

#### *3.4. Spare Time-Related Aspects*

Regarding spare time-related aspects, the following items were correlated to the crunning performances. In general, physical activities such as attending a gym, going to the park or going out with friends were positively associated to performance outcomes (Table 4).


**Table 4.** Differences in crunning test performances by spare time-related aspects. All estimates were adjusted for gender and age.

SE: Standard error; <sup>a</sup> Estimated through linear regression analysis. All estimates were adjusted for gender and age.

Furthermore, spending more time with parents and siblings seems to be associated with better performances.

#### *3.5. Cognitive/Neuropsychological Aspects*

In general, very low regression coefficients were found. Children with lower school marks had better crunning performances, such relation was present in either children practicing teams and individual sports (Table 5). No significant correlations were found between all the inhibitory control items and the crunning movement for children practicing team or individual sports, with higher times needed to select congruent, incongruent and control trials associated to lower times needed to perform the test. Working memory items were not correlated to the crunning performance.

**Table 5.** Associations between the crunning test performance and cognitive/neuropsychological aspects for team and individual sport practitioners.


SE: Standard error; <sup>a</sup> Estimated through linear regression analysis. All estimates were adjusted for gender and age.

Items related to the shifting of attention showed positive but very low correlations to crunning times (with higher number of errors and higher time to perform the test correlated to lower crunning performances), with the only exception of the time to recognize numbers and letters in children engaged in team sports, which revealed significant correlation but very low coefficients.

#### **4. Discussion**

With this investigation, we aimed to determine possible factors associated with the performance of the crunning movement. As expected, in our population of European children, males performed better compared to females and older children performed better than younger ones.

Such aspects have been reported by various authors across different motor domains. Tomkinson et al. [1] reported for a sample of over 2 million children performances, increases across age groups from 9 to 17 years old, with males performing better than females in terms of strength, power, agility and aerobic capacity. However, the results are in favour of females regarding balance, flexibility and coordination. Similar results are reported by another investigation in a sample of 3804 children ranging between 6 to 10 years of age. Again, boys perform better than girls regarding strength, power, speed, agility and aerobic capacity but not flexibility, with performance increases according to age [32]. Both aspects are consistent with growth and physical maturation [33,34].

#### *4.1. Demographic Aspects*

The results we obtained regarding the crunning movement performance show differences related to each country with better performances from the Portuguese children and worst performances from the Turkish children. It has to be noted that the Portuguese sample was composed only of male children, while the Turkish sample was composed only of female children. Such results are consistent with the general outcomes provided above. Furthermore, it is not uncommon to appreciate geographical differences when considering different populations of same age ranges, for example, regarding speed in the 20 m sprint between 6-year-old Greek (5.05 ± 1 s) [35] and Lithuanian boys (5.8 ± 1.2 s) [36], or for jumping performance of 10-year-old Colombian girls [20] (110.2 cm), Australian girls (103.25 cm) [37] or South African girls (149.3 cm) [38] in the standing long jump. Differences are also present between the same country when considering rural and city areas [39]. The authors of this latter study indicated that these differences between areas possibly influence individual habits and therefore the level of physical activity which each children experiences. A review by Carlin et al. [40] also analysed the association of environmental factors and levels of PA. The study associated increased levels of PA in neighbourhoods which provided facilities, parks and public equipment, and found the opposite for those with fewer facilities. Therefore, environmental and cultural aspects may possibly explain the difference reported between the test performance of each country within the present investigation.

#### *4.2. Sport and Spare Time-Related Aspects*

In the previous sections, the influence of habits regarding the activity levels was evaluated [41]. The results we obtained in this sample of European children confirm that positive habits and lifestyles are associated with improved performance of the crunning movement. For instance, the better results obtained in those children engaged in gym activities or those going out to the park in their spare time. Our results are in line with a systematic review analysing the relationship between outdoor time and PF in children [42]. The authors report an overall positive effect of outdoor time on PF, however, with no specific effect on musculoskeletal fitness. Another cross-sectional investigation aimed to understand how sedentary behaviours or screen time could affect motor skills in children aged 5–16 years [43]. Screen time in particular was associated with lower physical activity, with greater effects on adolescents compared to children and on girls compared to boys. This aspect, if linked to increased sedentary behaviours, could lead to increased fat mass and therefore decreased PF amongst children [44].

In addition, our results also show that children engaged in team sports performed better than those engaged in individual activities, independently of the activity intensity. Other investigations comparing individual and team sports have reported similar results, for example, Morano et al. [45] evaluated physical and psychological factors among children, finding that children engaged in team activities had better shuttle run results for aerobic performances compared to their peers who were engaged in individual sports, and were also less dissatisfied with their body image. Jukic et al. [46] examined the differences in fundamental motor skills in a sample of under-10 soccer players, indicating that greater motor skills were positively related to gross motor quotient and locomotion skills. School children's enjoyment and cohesion during sport activities can predict physical improvements, and those engaged in team sports show significantly higher levels of enjoyment [47]. Being engaged in team sports has also been associated in children with increased motor skill proficiency [48], with greater associations in boys compared to girls. When neurobiological integrations are analysed, it is possible to see that boys involved in team sports have thinner cortices in the frontal lobe compared to those engaged in individual activities. This aspect indicates a faster maturation of the frontal cortex related to an advantage of frontal areas functioning [49]. These are factors that altogether are determinant to adequately perform a complex skill as the crunning movement, which requires the use of upper and lower limbs simultaneously.

#### *4.3. Cognitive and Neuropsychological Aspects*

Relative to cognitive and neuropsychological aspects, two main findings have been associated to the performance. Firstly, academic achievement is negatively linked to the performance results and, secondly, cognitive function is not linked to crunning performance neither for children practicing team sports nor for those practicing individual sports. Our findings are generally in contrast with other investigations. Emerging literature has positively linked cognitive performance and academic achievement to sport performance [50]. Such associations are also seen in intervention studies where both cognitive functioning and academic achievement are increased following a physical intervention [51–53]. However, the majority of studies have proposed aerobic activity as the main typology of physical activity included within their interventions [54]. These interventions are seen to act by improving brain structure and function [4]. However, within our study, neither a longitudinal intervention was undertaken nor the crunning movement involves aerobic metabolism activation. It is possible that the nature of the crunning movement itself requires a different cognitive demand compared to the cognitive and neuropsychological measures assessed.

Limitations of this study are the following: (1) The sample for each country was collected within one school, therefore, it was not possible to evaluate specific local aspects but only broad geographical differences. (2) Not all countries had the availability of both male and female participants. (3) The classification for sport intensity was based on broad characteristics of sporting activities (i.e., soccer, basket, gymnastics, etc.), therefore it is not possible to associate specific aspects related to different approaches between countries. (4) Regarding the cognitive and neuropsychological assessment, not all children and adolescents from the different countries were screened because they were not present at the time of the evaluation. Therefore, the sample which is available for providing information regarding results for such aspects is restricted. Indeed, a broader sample would be required for greater consistency of the test. There is a need to identify the sensitivity of the test to specific physical qualities.

Therefore, it will be important in future investigations to compare the present results to other populations in order to verify the applicability of the findings here provided.

The present study is the first known study to have evaluated and tried to identify variables associated to the crunning movement. Therefore, it will be necessary to consider

gender and physical activity differences among individuals if planning to include the crunning test within a test battery.

#### **5. Conclusions**

The present investigation detected different factors associated with the performance of the crunning movement. These are related to lifestyle and cognitive factors which may influence performance of the crunning movement. These associated variables need to be considered when comparing the results of the crunning movement test, especially across populations. Special attention must be paid regarding gender and previously practiced physical activity. The specificity of the crunning test still needs to be understood within the context of a fitness evaluation.

**Author Contributions:** Conceptualization, A.B.; Data curation, A.B. and F.N. ¸S.; Formal analysis, E.T. and G.T.; Investigation, C.M.d.S., M.B., M.G.-L. and S.P.; Methodology, M.G.-L.; Project administration, M.A. and A.P.; Supervision, M.B.; Visualization, A.R.; Writing—original draft, E.T. and G.T.; Writing—review & editing, A.B., Ö.G. and D.J.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** The work was conducted within the ESA (Enriched Sport Activities) Program—Agreement number 2016-3723/001-001, funded by the Erasmus Plus Sport Programme (2017–2019) of the European Commission. Erasmus+ Sport Programme. EAC/A04/2015—Round 2 E+ SPORT PROJECT: 579661-EPP-1-2016-2-IT-SPO-SCP. Enriched Sport Activities Program.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Lithuanian Sports University's Institutional Review Board, approval No 579661-EPP-1-2016-2-IT-SPO-SCP (2018-02-05).

**Informed Consent Statement:** A parent or legal representative of each child signed a declaration of informed consent.

**Data Availability Statement:** Data available on request due to restrictions eg privacy or ethical.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

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