Assessment in the Supine-To-Stand Task and Functional Health from Youth to Old Age: A Systematic Review

Performance in the supine-to-stand (STS) task is an important functional and health marker throughout life, but the evaluation methods and some correlates can impact it. This article aims to examine the studies that assessed the performance of the STS task of young people, adults and the elderly. Evidence of the association between the STS task and body weight status, musculoskeletal fitness and physical activity was investigated, and a general protocol was proposed. MEDLINE/Pubmed and Web of Science databases were accessed for searching studies measuring the STS task directly; identification, objective, design, sample, protocols and results data were extracted; the risk of bias was assessed (PROSPERO CRD42017055693). From 13,155 studies, 37 were included, and all demonstrated a low to moderate risk of bias. The STS task was applied in all world, but the protocols varied across studies, and they lacked detail; robust evidence demonstrating the association between STS task and musculoskeletal fitness was found; there was limited research examining body weight status, physical activity and the STS task performance. In conclusion, the STS task seems to be a universal tool to track motor functional competence and musculoskeletal fitness throughout life for clinical or research purposes.


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].
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.

Study Selection
One author (MTC) conducted the identification of the studies, and added it to Rayyan QCRI, a web application for systematic reviews [27]. In this environment, the duplicates were removed by MTC. Before initiating the screening process, MTC and FSS performed an exhaustive training to include articles until they reached a concordance of the 92%; then, these two authors reviewed the list of titles for applying the inclusion criteria. So, the authors compared the results and discussed the discrepancies until they reach a consensus. If there was no consensus about a title, a third researcher resolved the disagreement (MPS). Such a process was repeated, reviewing abstracts and full texts, again applying the inclusion criteria. The identification of articles in the list of references and consultation with specialists supplemented the search strategy, added to the Rayyan application.

Data Extraction and Methodological Quality Assessment (Risk of Bias)
There was the extraction of the following data: Identification (author, year, and country of publication); objective, design, sample characteristics; STS outcome (process or product-oriented); results/conclusion strictly related to the STS task ( Table 1). The number of trials, instruction for performance pace, participant's caring, and motivational strategies from the protocols' studies were also extracted ( Table 2).
The quality of each article (risk of bias) was examined by 15 questions adapted from Law [28], and the scoring was as follows: 0 = does not meet criteria; 1 = satisfies the criteria; ? = not clearly described; NA = not applicable. In the classification, a study with score ≤ 7 = high risk of bias/low quality; studies that reached 8 to 11 points = moderate risk of bias/medium quality; scores ≥ 12 = low risk of bias/high quality (Supplementary material Table S1). Two researchers conducted these data extraction (MTC and FSS), and when there was no consensus, another researcher (ABD) resolved the disagreement.
The data were summarized in tables, and a narrative synthesis was done. Lastly, a full protocol was developed from the critical knowledge generated here. Some authors in this review worked in the clinical setting, and others are specialists in movement analysis, both in children and in the elderly. Then, the theoretical background and practical experience contributed to the presentation of this final protocol (Appendix A, Box A1).

Data Extraction and Methodological Quality Assessment (Risk of Bias)
There was the extraction of the following data: Identification (author, year, and country of publication); objective, design, sample characteristics; STS outcome (process or product-oriented); results/conclusion strictly related to the STS task ( Table 1). The number of trials, instruction for performance pace, participant's caring, and motivational strategies from the protocols' studies were also extracted ( Table 2).
The quality of each article (risk of bias) was examined by 15 questions adapted from Law [28], and the scoring was as follows: 0 = does not meet criteria; 1 = satisfies the criteria; ? = not clearly described; NA = not applicable. In the classification, a study with score ≤ 7 = high risk of bias/low quality; studies that reached 8 to 11 points = moderate risk of bias/medium quality; scores ≥ 12 = low risk of bias/high quality (Supplementary material Table S1). Two researchers conducted these data extraction (MTC and FSS), and when there was no consensus, another researcher (ABD) resolved the disagreement.
The data were summarized in tables, and a narrative synthesis was done. Lastly, a full protocol was developed from the critical knowledge generated here. Some authors in this review worked in the clinical setting, and others are specialists in movement analysis, both in children and in the elderly. Then, the theoretical background and practical experience contributed to the presentation of this final protocol (Appendix A, Box A1).

Results
In this review, from of 13,155 studies found, 37 articles were included ( Figure 2) [8,11,12,[14][15][16][17][20][21][22][23][24][29][30][31][32][33][34][35]. The studies investigated subjects ranging in age from 1 to 94 years; the largest proportion of studies investigated up to 100 subjects [11,14,17,31,[36][37][38][39][40], and one of them [41] examined a very large sample with 2368 subjects; more than a third of them used both process and product-oriented measurements (Table 1); only one study combined these two approaches creating a full score (MOD score) [40].   -Children with HCP performed the STS task using general MPs, but with reduced inter-individual variability compared to CG, with more asymmetrical patterns with systematic support on the unaffected side.   Hsue (2014) [21]; Taiwan To determine the within-and inter-rater reliability in classifying the MPs of STS task in TD children and children with mild to moderate DD.   Process-MPs categories (UE, AX, and LE regions) from VanSant [3] revised by Marsala and VanSant [12], and Belt et al. [40] Developmental capability tested by Peabody Developmental Motor Scale-II ( The TD group followed the proposed developmental sequences, as well as the DD group, which showed different maturation speed and more variability, especially between the age of 3 and 5 yrs.; the most used MPs by children with DD were at least one developmental categorical pattern behind those used by the age-matched TD children before 5 yrs. Old, except for the LE region. In the DD group, children with better motor performance used more developmentally advanced patterns. Children who scored higher on STS process also scored higher on MC process and were faster in the 10 m running time; a significant association between STS time and BMI (r = −0.508), STS time and STS process (r = −0.463), standing long jump distance (cm) and STS time (r = −0.414), and 10 m running speed (s) and STS time (r = 0.539). STS test is a measure of functional MC in children.

Nesbitt et al. (2017) [12]; US
To examine the relationship between qualitative (developmental sequences) and quantitative (time) performance rising from a supine position in early childhood.

Product-STS Time (s)
Process-MPs categories (UE, AX, and LE regions-VanSant [3]. BMI The children' STS task performance was quite variable in terms of qualitative MPs; STS mean time = 2.37 s, ± 0.60. The levels of the components of UE (r = -.383) and AX (r = −416) were correlated with time. Results indicated a strong association between trunk control development and UE (r = 0.791) movement levels, and together they demonstrated the strongest effect on STS performance. There was no association between BMI and time in the STS task. OBS/NP; 265 subjects ♂♀(children and adults) distributed in 4 age groups: 3-6 (mean age 4.8 ± 0.9 years); 9-12 (mean age 10 ± 0.8 years); 13-17 (mean age 14.9 ± 0.9 years); 18-25 (mean age 20.9 ± 2 years) OBS/NP; 72 adults, age range = 30-39 years (mean age = 34.1 ± 2.8 yrs.) divided into three groups: group 1 (n = 25) reported daily physical activity, group 2 (n = 26) reported exercising once or twice a week, and group 3 (n = 21) reported did exercises less than once a week.
More active people used more advanced MP than the rarely active ones. The lifestyle patterns of regular, moderate physical activity may influence the STS task performance. This study provided support for the use of developmental sequences for the MP of the STS task.

Didier et al. (1993) [43]; France
To compare the energetic costs of daily activities in young and older adults, such as rising and sitting back down on a seat, getting up from and lying down on a bed, and getting up from the floor.

Product-STS time (s). Energy Cost
Getting up from and lying down on the floor or a standard hospital bed involved the same energy cost in the older and younger group, but performing these activities took significantly longer for the older people Product-STS time (s); Process-from five different initial positions, with and without external support: (1) supine; (2) on the side; (3) prone; (4) all fours; and (5) sitting.
Perceived level of difficulty.
Older adults had more difficulty performing STS task than young. Healthy older adults took two times longer than adults to rise; congregate older adults took 2-3 times more than healthy older adults. Adults and healthy older adults rose from every position; Congregate older adults were most likely rising successfully from a side-lying position using furniture for support. The most capable subjects rose more quickly and had fewer difficulties when rising from the all-fours position. Seven task components were noted: Lying, initiation, positioning, supporting, and elevation stabilization followed by quiet stance or walking; older adults = 5.7 s vs. young adults = 3.7 s (p < 0.001).
There was a reduction in STS performance in older subjects, which was associated with reduced power and flexibility. Executive function, leg and hip power, and knee flexibility were lower in the older adult group. The scenario type did not influence the number of STS task components. - The motion sequences of the older adults were less fluent and smooth than in the younger group; older subjects used more indirect movement strategies, including more turns around the longitudinal axis to prepare for elevation. There was the feasibility of describing and discriminating the performance kinematics of younger and older subjects standing up from the floor from different lying postures, using inertial sensor signals at the trunk.

Elderly
Schenkman et al. [46] (2000); US About 80% of the women managed to perform the STS task and could cope with steps higher than 30 cm; younger subjects performed better than those in the higher age bands in all tests; all clinical tests correlated significantly with each other (range = 0.25-0.85) and also with the self-reported walking index (range = 0.32-0.62). Interventional/Random allocation; healthy older adults. Training group (n = 17, ♀ = 13; mean age = 81 ± 6 yrs.) submitted to an individual training in strategies to rise from the floor using key body positions; control group (n = 18, ♀ = 13; mean age = 80 ± 7 yrs.) submitted to an chair-based flexibility intervention.
Product 1-able or not able to perform the STS task in eight different conditions; Product 2-STS time.
The Perceived Scale of Symptoms and Difficulties.
The training group showed a significant improvement in the post-test mean number of rising tasks completed; regarding the supine position, the mean rise time varied from 21-25 s at baseline to 20-27 s post-intervention, but such improvement was not significant.
The training group showed a significant improvement in the level of difficulties and symptoms.

Bergland et al. (2004) [16]; Norway
To verify whether balance, function, and other health status indicators can predict serious fall-related injuries or fall-induced fractures in older women.
Product-scored whether the subject managed to perform the tasks without assistance (1 point) or not (0 points).
Other measures: Serious fall injuries over a year, health records, function, and walking and balance Rheumatic disorders and the inability to perform STS task were the most substantial independent risk factors for fall-related severe injuries.

Henwood et al. (2005) [47]; Australia
To investigate the effects of a short-term high-velocity varied resistance training program on physical performance in healthy community-dwelling older adults aged 60 to 80 years.

Product-STS time (s).
Muscle power and strength measures: Chair rise to standing, 6-m walk, lift and reach; BMI and percentage of body fat.
In Baseline, Experimental group STS time = 4.5 ± 0.8 s; control group STS time = 3.8 ± 0.9 s; after training there was 10.4% reduction in time in the experimental group from the baseline (p = 0.006). There was a group X time interaction for floor rise to standing (experimental group). There was no change in body composition during the study.

Bergland et al. (2005) [17]; Norway
To assess the concurrent and predictive validity of older women's ability to get up from lying on the floor.
Product-scored whether the subject managed to perform the tasks without assistance (1 point) or not (0 points).
Falls and falls-related injuries, function measures, and health and social resources.
The STS task is a valid marker of failing health and function in older adults and a significant predictor of serious fall-related injuries.

Flexibility of the glenohumeral and hip joints
There was a significant association between assisted-active flexibility and STS performance.

Naugle et al. (2012) [37]; US
To examine the association between compensatory strategies to successfully daily activities and body mass in pre-clinically disabled older adults.
Process-MOD Score evaluated (0 to 5 points) participants' performance on each task according to the severity of the compensatory strategy to complete the task.
Chair rise from three heights (43,38, and 30 cm), kneel to stand, stair ascent, stair descent, and lift and carry a basket filled with 10% of the subject's BMI.
The obese class II group had a higher likelihood of using one or more compensatory strategies while performing the STS task compared to all other groups. Individuals categorized as overweight and obese Class-I were more likely to use compensatory strategies while performing the STS task than the healthy weight group.

Raso and Greve (2012) [50]; Brazil
To determine the effect of an aerobic or resistance exercise protocol on the performance of daily living activities in older women.

Product-STS velocity (s).
Performance in these tasks was measured while subjects were wearing sneakers: Sitting to standing position, STS task, and climbing stairs.
Subjects of the aerobic exercise protocol improved speed significantly when wearing sneakers, while subjects of the resistance exercise protocol improved their performance in the STS task and climbing stairs when using these shoes. To investigate the impact of an ambulatory physical activity program on the motor skills of retirees Interventional, not controlled study/NP. N total = 200 living home healthy older adults (♀ = 172), age range = 60-100 yrs. (mean age = 73.8 ± 7.4 yrs.). They were divided into two groups for STS task: Robust subjects vs. frail or very frail subjects. The program included strengthening muscular and joint flexibility exercises, balance work, one-leg-balance test, stimulation of the foot arch, STS task, TUG, gait speed, one-leg-balance Product-able or unable to perform the STS task.
One-leg-balance test, TUG, gait speed, one-leg-balance test duration For STS, 81% of participants did not change groups after training program, 18.5% changed from (very) frail to robust, and 0.5% of subjects changed from robust to (very) frail.  Just four studies reported the verbal instructions on starting position, which included legs extended and arms extended to the side of the trunk [14,31,36,40] five studies reported the final position as stable standing upright with both feet on the ground [23,24,31,38,40]. Nesbitt et al. [8] used final position goal combined with touching a designated point on the wall; Alexander et al. [4] asked the subjects to press a switch placed on a tripod when assuming the standing position, marking the end of the task. Other protocols' characteristics were summarized in Table 2.
None of the studies that investigated the STS task were classified as high risk of bias. However, the item most frequently absent in assessing the risk of bias was "Was the justification for the sample size?", with only 18.9% of studies presenting such a justification (for detailed information, see Supplementary Material Table S1). Table 2. Absolute and relative frequencies of the protocols' characteristics of studies reviewed about the Supine-to-Stand (STS) task (n = 37).

N f (%)
Quality of study

The STS Task Performance and Body Weight Status, Musculoskeletal Fitness and Physical Activity
By investigating young children, Ng et al. [31] and Nesbit et al. [12] did not find an association between STS time and BMI; by investigating older children, Duncan et al. [11] found a moderate inverse correlation (r = −0.508). Naugle et al. [37] investigated older adults and found that each unit of BMI was associated with an increase in the severity of compensatory strategies to rise; also investigating older people, Manckoundia et al. [38] found that being overweight was associated with fails to perform STS (not able to rise); Henwood and Taaffe [47] investigated the effect of a fitness program in seniors and found a positive effect on STS time. Belt et al. [42] investigated people from ages 7 to 36 years with Prader-Willi syndrome and typical controls, and regardless of diagnosis, they found a very poor correlation between STS task process measurement and BMI, but there were not confirmed relationships between BMI and any of the three body region scores. However, some cautions are need because BMI at different ages is related to various components of body composition.
Four studies investigated the relationship between STS task performance and musculoskeletal fitness, which showed a direct relationship [23,32,33,39]. One investigated children by testing grip and trunk muscle strength [32]; lower limb power of the older people were investigated [23,33,37,39], as well as flexibility [23] and upper limb strength [39]. One study [20] investigated a musculoskeletal training intervention on STS time performance in seniors that showed a positive effect.
Two studies examined the association between STS task performance with physical activity [14,39]. Green and Williams [14] investigated 72 middle-age adults and noted that the most active adults used more advanced STS task patterns than those who were rarely active, but they did not perform an inferential test. Klima et al. [39] investigated older adults and found an inverse correlation between STS task time and physical activity level (rho = −0.29).

Discussion
In this present review, the methods used in the STS assessment were summarized and critically examined. Furthermore, this review verified the association of STS task performance with select health variables. The results showed that the STS task performance was investigated throughout the life cycle, in various countries, and several studies used large samples [3,12,[15][16][17]31,[36][37][38]. In general, these results suggest the STS task can be considered a functional health assessment, from youth to old age.
However, the measurement type can be a critical issue. For example, by using a dichotomous variable (to be able or not gets up from the floor), Bergland et al. [15][16][17] investigated seniors (over 75 years) and concluded that the STS task is a valid marker of health and function problems, as well as a significant predictor of falls-related severe injuries in this life phase. One's ability to stand up is a validated measure; however [15], it does not reveal the phenomenon of functional MC throughout life, since it seems to have been very suitable for use in the sample of older subjects, but it must have a ceiling effect at younger ones.
Both process and product-oriented measurements were used in a similar proportion in the literature. Process-oriented measurement identifies the difficulties in the task but demands much time to code and seems to be more valuable to propose intervention, mainly in older adults. Alternatively, product-oriented measurement, as movement time, maybe more related to functional outcomes. Facing a challenge, such as standing up as fast as possible, and relating this outcome to functional capabilities, like muscular strength and endurance, speaks to the ability to solve a functional motor task in various ways and at various speeds. This task speaks to the importance of being able to vary the execution of STS based on specific task demands. Thus, STS time is a resourceful way to operationalize functional MC, mainly with large samples or studies with many variables, as it requires limited technological resources and provides better discrimination and sensitivity in measurement than process-oriented assessments.

Risk of Bias and Procedure Protocols
Since all studies showed a moderate or low risk of bias, the internal validity was considered satisfactory. The more comprehensive analysis of the STS protocols showed a wide variety of procedures, which can be a severe problem if one proposes to have one protocol to be used for all the developmental levels. The instruction on the mechanics of the movement can facilitate performance [34,35] so for an understanding of how people typically get off the ground, controlling the instructions is critical to STS assessment. All studies instructed subjects individually, and most of them relied on verbal information rather than demonstration; some researchers even explicitly prevented any visual demonstration or explanation of the STS mechanics [11]. In summary, it was clear that researchers avoided any modeling or verbal instruction bias to examine the movement patterns typically used by participants.
Also, the time constraint instruction needs to be highlighted, since maximum speed instruction can affect the automaticity of the movements (i.e., minimizing the conscious analysis of the motor action) [53]. An external focus of attention (i.e., time restriction) organizes the motor system according to individual constraints and choice, rather than when the focus of attention is internal (i.e., on a movement pattern), which can interfere with the automatic process control as explained by the "constrained-action hypothesis" [35,53]. Depending on the measurement intents, a researcher can choose whether to impose a time constraint. For instance, to examine a general STS movement process that individuals would use in everyday life, a time constraint would not be necessary. Alternatively, to examine functional capacity as it relates to a "best" or "maximal" performance, a time constraint may be the most appropriate option. The time factor may be a more salient choice to predict health outcomes as the ability to produce power has strong implications for all-cause mortality and functional independence in older adults [54], as well as fitness, physical activity, and weight status in youth and young adults [5,55,56].
The final position of the task is another critical element related to the instructions. Two studies combined the goal of postural alignment with an external target [4,12]. This seems to be an efficient methodological strategy, since the performer has a simple and easy-to-execute external goal (touching the point in front of him/her), and in turn, the evaluators' job is facilitated to stop the chronometer or video frame. However, understanding whether providing a final position with an additional reaching task might alter how an individual stand needs to be addressed.
Regarding feedback and rewards, three studies detailed the procedures given to motivate children by using verbal reinforcement during or after the task execution, using praise or words highlighting their efforts [3,12,24]. Motivational feedback was used only with early childhood children, since the motivational climate can dramatically affect preschoolers' performance [55]. Encouraging may be highly beneficial if the time task constraint is "maximum" (i.e., shortest time) [40].
The number of repetitions varied widely among the studies. This lack of uniformity weakens the findings as a high number of repetitions without adequate rest can cause fatigue, adversely affecting motor performance. It seems to be the case with older or frail individuals that demonstrate limited physical function and fitness. Conversely, only one trial may not represent typical behavior. When addressing the movement process, two to five trials would be necessary to gain insight into an individual's most probable movement process.

STS Performance and Body Weight Status, Musculoskeletal Fitness, and Physical Activity
Seven studies examined the body weight status and the STS task performance, and three of them demonstrating significant associations. It seems reasonable to expect that weight status, specifically with increased adipose tissue, is associated with STS performance. In overweight or obese individuals, the motor system has to overcome higher inertia to accelerate the body mass against the force of gravity to attain an upright position. Individuals can accomplish these using variable body actions that may not require high power outputs. Rather, maximizing postural alignments that minimize the demand for high muscle activity levels (i.e., manipulation of multiple degrees of freedom with minimum energy expenditure) would be a favorable strategy for individuals who demonstrate low muscular power/strength and endurance. However, while these strategies may be useful for minimizing energy expenditure, they may increase the time to stand. This potential trade-off may also speak to the variability in individuals' MC. If individuals demonstrate higher MC levels, they may be able to stand using different coordination patterns regardless of energy used (i.e., level of neuromuscular demand or segmental coordination patterns), as demonstrated in Didier's study [43]. However, individuals with low levels of overall MC may be more restricted in their movement patterns, due to a lack of muscular strength or coordinative capabilities across multiple joints. It is possible to think that the bodyweight status is a good candidate to be a moderator variable to the STS task performance, playing a role integrated with other fitness variables. More scientific pieces of evidence are necessary on this topic. This review has confirmed there is a positive association between the STS task performance and musculoskeletal fitness for all ages, confirming previous literature results [5,6,55]. Therefore, it seems the STS is a good candidate to be a musculoskeletal health indicator in all cycle life. The association between STS task performance and physical activity was examined in only two studies [14,39]. Even though the results had agreed with each other, and both studies have shown a low risk of bias, they have used different approaches, and one of them [14] did not report inferential associations. Thus, it seems too early to state that there is evidence of a direct association between physical activity and STS task performance. A previous study [56] has supported the notion of reciprocal action between the physical activity and MC, and perhaps it was the case of thinking more about how they enhance each other than just the simple relationship between them.

Clinical Applications
Hofmeyer et al. [20] carried out the only study that tested training for getting off the ground: Their results showed an improvement in the experimental group performance compared to the controls. This study reinforces that the STS task also has interventional value to health professionals. By taking all results of this review, one can generally state that STS is a potentially useful tool to examine functional MC and a general health status marker, as well as a useful approach to clinicians and researchers. It is notable in the present review that the STS task was investigated in the stages of childhood, adulthood, and old age. These results allow us to recognize that this is a task that is appropriate to play at all ages; in particular, a measure of the STS time has shown to have sufficient variability to distinguish individuals in all ages, without having a ceiling or floor effects.
The upright posture enables the subject to dominate his environment, and righting behaviors is an expression of physical independence [1]. Also, achieving such an upright posture in the shortest possible time, challenging individual constraints (e.g., unfavorable weight status), is a clear expression of human motor competence, i.e., the ability to solve motor problems in the face of challenging demands from the environment or of the subject itself. However, more evidence across the lifespan is needed to demonstrate these linkages.
Even the results of this review allow affirming that the STS task has a strong potential to uncover MC at any phase of life, the studies used diversified protocols and methodological strategies along with what prevented comparison and the generalization of findings. So, as a by-product of this review, a unique and universal protocol is proposed (Appendix A). We also understand that we are in agreement with contemporary literature on this subject. A very recent article [52] researched the same task with minor differences, showing its importance for older adults and investigating its clinimetric properties. We reinforce and extend the results of this study because we proposed that this task can be tested for all ages.

Study Strengths and Limitations
The strength of this study was that it examined all STS literature across the lifespan, and disentangled the various methods used to assess this task in several countries. It is plausible to present STS as a good candidate for a valid and non-culturally biased measure of functional MC across the lifespan. It is also advantageous to have a unique protocol that can be applied across all ages to facilitate tracking motor competence over time. The limitations of this study were that only studies in English were reviewed. Moreover, since the objective of this study was only to review methods, other studies should be carried out to establish typical values and significant cutoff points for the STS task performance.

Conclusions
This review showed that the STS task was tested at all ages, in various parts of the world, confirming it as a useful tool to track functional motor competence throughout life, in a universal way. In particular, measuring the time of the STS task is an ingenious way to operationalize functional motor competence mainly in large-scale studies. In addition, as it was found that the STS task has a strong relationship with musculoskeletal fitness over the years, it can help to monitor this health variable throughout life. It is not yet possible to recognize a factual relationship between the performance of the STS task and health variables, such as body weight status and physical activity.