J. Funct. Morphol. Kinesiol., Volume 3, Issue 4 (December 2018) – 15 articles

Background: The effects of proprioceptive neuromuscular facilitation (PNF) stretching on muscle imbalance are not fully understood. The aim of this study was to examine the acute effects of PNF stretching on knee extension and flexion peak torque (PT), as well as the conventional and functional hamstrings to quadriceps (H:Q) ratios. Methods: Fifteen men (age = 22 ± 1 years; body mass = 76 ± 12 kg; height = 176 ± 7 cm) and fifteen women (age = 22 ± 2 years; body mass = 63 ± 8 kg; height = 161 ± 5 cm) performed concentric quadriceps and hamstrings, and eccentric hamstrings muscle actions at different angular velocities (60, 180, and 300°·s⁻¹ concentric; 60 and 180°·s⁻¹ eccentric) before and after a bout of PNF stretching, and a control condition. Results: Neither PNF or control conditions affected concentric PT or H:Q ratios (p > 0.05), apart from knee extension at 60°·s⁻¹ in men (p = 0.001). However, there was a reduction in hamstrings eccentric PT in both control and PNF conditions for men and women (p = 0.003). Conclusions: PNF stretching of the hamstrings may not adversely affect the H:Q ratios, and consequently not negatively affect injury risk associated with muscular strength imbalances. Full article

The effects of long-term high-protein consumption (i.e., >2.2 g/kg/day) are unclear as it relates to bone mineral content. Thus, the primary endpoint of this investigation was to determine if consuming a high-protein diet for one year affected various parameters of body composition in exercise-trained women. This investigation is a follow-up to a prior 6-month study. Subjects were instructed to consume a high-protein diet (>2.2 g/kg/day) for one year. Body composition was assessed via dual-energy X-ray absorptiometry (DXA). Subjects were instructed to keep a food diary (i.e., log their food ~three days per week for a year) via the mobile app MyFitnessPal^®. Furthermore, a subset of subjects had their blood analyzed (i.e., basic metabolic panel). Subjects consumed a high-protein diet for one year (mean ± SD: 2.3 ± 1.1 grams per kilogram body weight daily [g/kg/day]). There were no significant changes for any measure of body composition over the course of the year (i.e., body weight, fat mass, lean body mass, percent fat, whole body bone mineral content, whole body T-score, whole body bone mineral density, lumbar bone mineral content, lumbar bone mineral density and lumbar T-score). In addition, we found no adverse effects on kidney function. Based on this 1-year within-subjects investigation, it is evident that a diet high in protein has no adverse effects on bone mineral density or kidney function. Full article

The purpose of this study was to empirically test a comprehensive conceptual model linking gross motor skills, school day physical activity and health-related variables in a sample of sixth graders. Participants were a convenience sample of 84 sixth grade students (Mean age = 11.6 ± 0.6 years). Gross motor skills were assessed using the Test of Gross Motor Development-3rd Edition (TGMD-3), school day physical activity was assessed using pedometers, health-related fitness was assessed using Progressive Aerobic Cardiovascular Endurance Run (PACER) laps, perceived competence assessed using a validated questionnaire and the health-related outcome was assessed using Body Mass Index (BMI). The relationship between school day step counts and TGMD-3 scores was mediated through both perceived competence and PACER laps (p = 0.015) and the direct path coefficient between TGMD-3 scores and BMI was statistically significant (b = −0.22 kg/m², p < 0.001). Overall there was good model fit with all indices meeting acceptable criteria (χ² = 3.7, p = 0.293; Root Mean Square Error of Approximation (RMSEA) = 0.062, 90% Confidence Interval (C.I.): 0.00–0.23; Comparative Fit Index (CFI) = 0.98; Tucker-Lewis Index (TLI) = 0.96; Standardized Root Mean Square Residual (SRMR) = 0.052). The comprehensive conceptual model explaining the inter-relationships among motor competence and health-related variables was empirically validated with the relationship between physical activity and gross motor skills mediated through both perceived competence and cardiorespiratory endurance in a sample of sixth graders. Full article

The aim of this study was to analyze blood lactate concentration (LAC), heart rate (HR), and rating perceived exertion (RPE) during and after shorter and longer duration CrossFit^® sessions. Nine men (27.7 ± 3.2 years; 11.3 ± 4.6% body fat percentage and training experience: 41.1 ± 19.6 months) randomly performed two CrossFit^® sessions (shorter: ~4 min and longer: 17 min) with a 7-day interval between them. The response of LAC and HR were measured pre, during, immediately after, and 10, 20, and 30 min after the sessions. RPE was measured pre and immediately after sessions. Lactate levels were higher during the recovery of the shorter session as compared with the longer session (shorter: 15.9 ± 2.2 mmol/L/min, longer: 12.6 ± 2.6 mmol/L/min; p = 0.019). There were no significant differences between protocols on HR during (shorter: 176 ± 6 bpm or 91 ± 4% HRmax, longer: 174 ± 3 bpm or 90 ± 3% HRmax, p = 0.387). The LAC was significantly higher throughout the recovery period for both training sessions as compared to pre-exercise. The RPE was increased immediately after both sessions as compared to pre-exercise, while there was no significant difference between them (shorter: 8.7 ± 0.9, longer: 9.6 ± 0.5; p = 0.360). These results demonstrated that both shorter and longer sessions induced elevated cardiovascular responses which met the recommendations for gains in cardiovascular fitness. In addition, both training sessions had a high metabolic and perceptual response, which may not be suitable if performed on consecutive days. Full article

Spine curvature disorders are very common in the population. Several therapeutic methods have been implemented over time. Kinesio Taping (KT) is a solution that is utilized for several purposes. This narrative review aims to discuss KT methodology as a valid solution for spinal curvature disorders, especially for structured and non-structured spine deviations. The matter is poorly discussed in the current literature. Nevertheless, KT seems to indirectly influence posture and spine curvature disorders through peripheral and central nervous system stimulation, but further investigations are needed to demonstrate these unknown effects clearly. The present review provides a valuable contribution to the existing literature and may represent a starting point and a useful guide for further studies in this field of research. Full article

The current submission was conceived to broaden the discussion around male athletic identities by exploring the stories told by four members of the Canadian National Boxing Team. The athletes’ stories were elicited through an arts-based method followed by a conversational interview. Stories were then analyzed using an interpretive thematic analysis. Three salient themes were found—fluid masculinity, ethnicity brings an edge to boxing, and expressing identity through language. These themes present accounts that highlight how socially, culturally, and historically dominant narratives can allow athletes to feel comfortable in presenting the identities they might reveal or feel constrained from doing so due to factors outside of their control. The need to develop training and competition contexts that allow for the empowerment of athletes’ individually distinct identities is highlighted as a method to ensuring the positive mental health of elite level athletes. Full article

Background: This cross-sectional study aimed to examine associations between motor competence, physical activity, and obesity in British children aged three to five years. Method: Motor competence (MC) was assessed using the Test of Gross Motor Development-2. Physical activity (PA) was assessed using triaxial wrist-worn accelerometers. Children were assessed on compliance to current PA recommendations of ≥180 min of total PA (TPA) and ≥60 min of moderate-to-vigorous PA (MVPA) for health benefits. Associations were explored with Pearson’s product moments and weight-status, and sex-differences were explored with independent t-tests and chi-squared analysis. Results: A total of 166 children (55% males; 4.28 ± 0.74 years) completed MC and PA assessments. Associations were found between PA and MC (TPA and overall MC, TPA and object-control MC (OC), MVPA and overall MC, and MVPA and OC). This study suggests that good motor competence is an important correlate of children meeting physical activity guidelines for health. Full article

Background: As the knee joint is a common site for injury among younger people, the purpose of this study was to measure the skeletal muscle endurance and strength on people with prior anterior cruciate ligament (ACL) knee reconstruction surgery. Method: Young healthy female subjects who reported having knee reconstruction surgery more than one-year prior were tested. The skeletal muscle endurance index (EI) of the hamstrings and quadriceps muscles was determined as the decline in the specific muscle acceleration in response to 2 Hz, 4 Hz, and 6 Hz electrical stimulation. Maximal isometric muscle strength (MVC) was measured in the hamstrings and quadriceps muscles. Results: The hamstrings muscles in the injured leg had less endurance than the non-injured leg at 6 Hz stimulation (55.5 ± 13.2% versus 78.0 ± 13.3%, p < 0.01). Muscle endurance was not reduced in the quadriceps muscles in the injured leg compared to the non-injured leg at 6 Hz stimulation (78.0 ± 13.3% versus 80.3 ± 10.0%, p = 0.45). There were no differences in MVC between the injured and non-injured legs for either the hamstrings (p = 0.20) or quadriceps muscles (p = 0.67). Conclusions: Muscle endurance was reduced in the hamstrings muscles at least one-year post injury, while hamstrings strength was recovered. Reduced hamstrings muscle endurance could be a result of lack of endurance training during rehabilitation. This may contribute to re-injury in the muscle, even in people who have recovered muscle strength. Full article

Resistance training (RT) is considered the most important method to improve the athlete’s strength and rate of force development (RFD). In the last decade, the importance of monitoring velocity during RT has drastically grown, because of an increased availability of linear position transducers (LPT) and inertial measurement units (IMU). The purpose of this review is to analyze the existing literature on testing techniques and performance strategies used to enhance strength and power performance of elite athletes, by monitoring the velocity of resistance training. The authors focus in particular on the level of effort of resistance training defined by velocity; how the loss of velocity correlates with the degree of fatigue and how it can be used to enhance the performance of competitive athletes; the use of LPT as part of the daily routine of the strength and conditioning programs in competitive sport. It is therefore critical for the sports scientists to have a correct understanding of the basic concepts of the velocity-based training and their application to elite sports. The ultimate goal is to give some indications on the velocity-based resistance training integration in the programs of different sports in the high performance environment. Full article

Assessing function in elderly populations predominantly aims to quantify the risk of falling. Current assessment methods do not consider changes associated with aging in movement coordination patterns and the ability to control movement. The aim of this study was to examine the intra-rater reliability of a ‘Movement Screening Test’ (MST) in females over 80 years across a range of physical activity levels, who were golfers and non-golfers. Female recreational golfers (N = 21) and non-golfers (N = 10) aged 80 to 87 years performed the MST. The MST consists of three tests: Test 1, sit to stand with arm lift; Test 2, trunk lean with knee bend and opposite arm lift; Test 3, chest rotation with neutral head and pelvis. Videos of the MST were analyzed and scored according to specific criteria. The videos were reviewed on two separate occasions to quantify the intra-rater reliability of scoring of the MST. Intra-rater reliability ( $\mathsf{\kappa }$ ) of the MST demonstrated substantial agreement for 11/23 criteria ( $\mathsf{\kappa }$ = 0.65 and to 0.78) and excellent agreement for 9/23 criteria ( $\mathsf{\kappa }$ = 0.81 to 1). Therefore, the reliability of the MST for women aged 80 years and over was established. The MST test and scoring system may be further refined to improve reliability. Further investigations could explore coordination patterns in older people, how these relate to various aspects of musculoskeletal function, and how they vary between different populations. Full article

The optimal management of sarcopenia requires appropriate endpoint measures to determine intervention efficacy. While hand grip strength is a predictor of morbidity and mortality, lower extremity strength may be better associated with functional activities in comparison to hand grip strength. The purpose of our study was to examine the comparative association of upper and lower extremity strength with common measures of physical performance in older adults. Thirty community-dwelling men, aged 62.5 ± 9.2 years, completed body composition analysis, quantitative strength testing, and performance-based tests of functional status. Hand grip force values were not significantly associated with knee extensor or flexor torque values (p > 0.05). Hand grip force was only associated with fast gait speed, while knee extensor torque at 60°/s was the only variable significantly associated across all functional outcome measures: customary gait speed, fast gait speed, sit to stand time, and the Physical Performance Test (p < 0.02). Hand grip strength was not a proxy measure of lower extremity strength as assessed in this study. Overall, lower extremity muscle strength values had the strongest associations with participant functional performance. Lower extremity strength testing may provide additional value as an endpoint measure in the assessment and clinical management of sarcopenia. Full article

Background: This study compared differences between a control group and a group with unilateral ankle dorsiflexion restriction in the ground reaction force (GRF), angles of the lower limbs joints, and muscular activity during a rebound-jump task in athletes who continue to perform sports activities with unilateral ankle dorsiflexion restriction. Methods: The athletes were divided into the following two groups: The dorsiflexion group included those with a difference of ≥7° between bilateral ankle dorsiflexion angles (DF), and the control group included those with a difference of <7° between the two ankles (C). An ankle foot orthosis was attached to subjects in group C to apply a restriction on the right-angle dorsiflexion angle. The percentage of maximum voluntary contraction (%MVC) of the legs musculature, components of the GRF, and the hip and knee joint angles during the rebound-jump task were compared between groups DF and C. Results: Group DF showed increased %MVC of the quadriceps muscle, decreased upward component of the GRF, decreased hip flexion, and increased knee eversion angles. Conclusions: This study highlighted that athletes with ankle dorsiflexion restriction had significantly larger knee eversion angles in the rebound-jump task. The reduced hip flexion was likely caused by the restricted ankle dorsiflexion and compensated by the observed increase in quadriceps muscle activation when performing the jump. Full article

Suspension Training (ST) workouts include a variety of movements requiring the individual to maintain balance while performing various resistance exercises in an interval fashion. Although ST is thought to elicit higher muscle activations than traditional exercises, only limited information is available on its acute effects on strength and power performances, especially in relation to gender. Therefore, the purpose of this study was to evaluate the strength and power acute responses after ST, also in relation to gender. Eighty-eight (46 males, 42 females) participants were administered countermovement jumps (CMJ), squat jumps (SJ), lower limb Maximum Voluntary Contraction (MVC) at 90° angle knee extension, and grip strength (handgrip) before (PRE) and after (POST) a 50 min ST session involving upper, lower body and core exercises. ANOVA for repeated measures was used to evaluate the differences (p < 0.05) in relation to gender and experimental session. After ST session, significantly higher values emerged in males, whereas no significant changes were found in females. Findings indicate that ST as a form of exercise is useful to maintain and improve acute strength and power performances, especially in male participants. Future studies should be carried out to explore the gender-related differences in response to acute bout of ST exercises. Full article

This study compared sex responses for strength and barbell velocity from very short-term resistance training (VST, consisting of 2–3 training sessions) for an upper body dynamic constant external resistance (DCER) exercise (bench press [BP]). Ten females (mean ± standard deviation (SD) age: 21.3 ± 3 years, height: 166.2 ± 6 cm, body mass: 71.4 ± 10.7 kg) and 10 males (mean ± SD age: 24.6 ± 4 years, height: 179.5 ± 8 cm, body mass: 88.6 ± 11 kg) completed a pre-test visit to determine the BP 1 repetition maximum (1RM) as well as the mean (BP_MV) and peak (BP_PV) barbell velocities from the BP 1RM. The VST involved three training visits where the participants performed 5 sets of 6 repetitions, at 65% of the 1RM. The post-test followed the same procedures as the pre-test visit. There were significant increases in 1RM strength for both the males (5.1%) and females (5.4%) between pre-test and post-test. There were no significance differences between sex for mean (BP_MV) and peak (BP_PV); however, overall there was a 32.7% increase in BP_MV and a 29.8% increase in BP_PV. These findings indicated an increase in strength and barbell velocity for both males and females as a result of VST upper body DCER exercise in untrained subjects. Full article

We are glad to introduce the tenth Journal Club. This edition is focused on several relevant studies published in the last years in the field of athletic training, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture. Full article