**1. Introduction**

The human development lifespan perspective provides a framework for studying the changes that occur throughout life [1,2]. Within this perspective, some motor actions are considered developmental milestones and health indicators as the action "rising from a supine position on the floor to an erect standing position" (supine-to-stand, STS), since it is an indicative of bipedal readiness for upright locomotion in children [3] and functional capacity for independence in the elderly [4].

The STS task performance also uncovers an individual's level of motor competence (MC), defined as the proficiency in motor actions performed with coordination and control [5–7]. The STS task requires complex coordination of large muscle groups of the trunk and extremities, while controlling their center of mass in dynamic balance during elevation and stabilizing body alignment during the erect posture [8].

During the 1980s, Ann Vansant proposed developmental sequences for this righting task [1,3,9]. Studies related it to physical fitness and lifestyle variables [10–12] expanding the focus of motor development *per se*, to the discussion concerning their relationship with health [6,7]. STS has been investigated at different stages of life [4,8,12–14], and unlike other motor skills, such as running or jumping, instruction on how to rise from supine is not taught, which reduces the bias of cultural context or structured practice opportunities. Furthermore, the STS task seems to be a useful marker of health and function problems, predicting serious fall-related injuries [15–17].

With these characteristics, maybe the STS task is a useful and practical method to monitor functional MC changes throughout human life and an excellent candidate to be a universal screening tool. However, such assumptions need further examination. For example, health variables as physical activity, musculoskeletal fitness, and body status weight should be considered when evaluating the STS task [14].

Assessing the performance of the STS task or other motor action may involve two different measurement approaches: process and product-oriented. A process-oriented measurement aims to express the quality of the movement, in general, by comparing it with the more successfully mechanical form, as described in the checklists. A product-oriented measurement aims to describe the action results, such as the time to complete a task or the scores on a target, using interval or discrete variables (e.g., seconds, points, speed). Both approaches, complementary, expresses human motor performance [18,19]. Studies using a product-oriented approach measured the STS time by chronometers [20], photoelectric cells [4], or a video [8,12,14,21–24]. STS process-oriented measurements often uses video recordings, to check the postures [23] or motion sequences [9,10]. Such protocols do not always control procedures as verbal instructions or the number of trials. All of these differences lead to non-standardized performance reporting. As far as we know, there are no studies that have established a full protocol for assessment of the STS task for all ages.

According to PICO strategy, the research problem presented in this study asked if, in typical development individuals (P), the assessment of the STS task performance (I) used in different developmental phases (C) can monitor healthy functional MC changes (O). In this context, the main objective was systematically reviewing the supine-to-stand task assessment methods and the health variables related to this task in youth, adults, and older adults. Specifically, it was examined: [1] The methods used to investigate the STS task, including the risk of bias, and the results, [2] the evidence of an association between the performance of the STS task and the health-related variables body weight status, musculoskeletal fitness, and physical activity. Finally, as a by-product of this review, a protocol for STS task measurement, which is testable across the lifespan, was proposed.

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

The present review included studies of the several designs (observational, interventional, cross-sectional, longitudinal), so it can be better classified as a mixed-methods review [25]. This study is registered in PROSPERO (#CRD42017055693) and followed protocols for systematic reviews PRISMA-P [26].

#### *2.1. Data Sources and Searches Descriptors*

In this review, studies with healthy individuals in the phases of childhood, adolescence, adulthood, and senescence whose performance on the STS task had been assessed through objective measures, but not questionnaires, were searched. The databases were directedly accessed (MEDLINE, Scielo, EMBASE, Scopus, ERIC/ProQuest), and also it was used some search device (PubMed, Web of Science—Main Collection, Science Direct, EBSCO, Cochrane). Subsequently, the search involved gray literature, through the review of the reference lists (only of the included articles, see below) and

consultation with specialists in the area. Intragroup descriptors were combined using the Boolean expression OR, whereas between-group descriptors were combined using AND (Figure 1). Inclusion criteria were: (1) Original studies (articles, theses, dissertations) assessing the STS task by using objective measures, (2) English language, (3) healthy/typical development individuals. Exclusion criteria were: (1) Duplicates, (2) not match with the background of this review, (3) not typical individuals, (4) articles not available in full text. There were no restrictions on the year of publication.


**Figure 1.** Descriptors used in the systematic review about the supine-to-stand (STS) task performance, according to research tools in the databases. The figure was originally created by the authors.
