Efficacy of an Audio-Based Biofeedback Intervention to Modify Running Gait in Female Runners.

CONTEXT: A variety of gait retraining interventions are available to modify running mechanics associated with musculoskeletal injuries. These often require specialized equipment and/or personnel to prompt the runner toward specific strategies. OBJECTIVE: To determine whether instructing female recreational runners to "run quietly" could decrease impact force characteristics. DESIGN: Cohort. SETTING: Research laboratory. PARTICIPANTS: Fifteen healthy female recreational runners (24 [7] y) volunteered. INTERVENTIONS: Baseline testing occurred on day 1 (baseline), a posttraining assessment occurred on day 2 (training), and a final assessment occurred 1 week after training on day 3 (follow-up). A smartphone decibel measuring app was used to provide biofeedback on the decibel level of foot strike on day 2 (training). MAIN OUTCOMES: Peak vertical force, impact transient, peak and average vertical loading rate, ground contact time, and running economy were collected on each day and compared via repeated-measures analyses of variance. RESULTS: Vertical ground reaction force was lower at follow-up (2.30 bodyweights [BW]) versus baseline (2.39 BW, P = .023) and training (2.34 BW, P = .047). Maximal loading rate decreased from baseline (69.70 BW·s-1) to training (62.24 BW·s-1, P = .021) and follow-up (60.35 BW·s-1, P = .031). There was no change in running economy. CONCLUSIONS: Our findings demonstrate that simple instructions to "run quietly" can yield immediate and sustained reductions in impact force profiles, which do not influence running economy.

The Effects of an Integrative, Universally Designed Motor Skill Intervention for Young Children With and Without Disabilities.

Many interventions feature a singular component approach to targeting children's motor competency and proficiency. Yet, little is known about the use of integrative interventions to meet the complex developmental needs of children aged 3-6 years. The purpose of this study was to examine the effects of an integrative universally designed intervention on children with and without disabilities' motor competency and proficiency. We selected children (N = 111; disability = 24; no disability = 87) to participate in either a school-based integrative motor intervention (n = 53) or a control condition (n = 58). Children in the integrative motor intervention both with and without disabilities showed significant improvement in motor competency and proficiency (p < .001) as compared with peers with and without disabilities in a control condition. Early childhood center directors (e.g., preschool and kindergarten) should consider implementing integrative universally designed interventions targeting multiple aspects of motor development to remediate delays in children with and without disabilities.

Novice Users of a Bodyweight-Supporting Treadmill Require Familiarization.

CONTEXT: Previous work has demonstrated an improvement in running economy during sustained running on a lower body positive pressure treadmill, but neuromuscular and spatiotemporal measures have only been investigated during short-duration running bouts on these devices. The current study sought to replicate the noted metabolic response and investigate whether neuromuscular and/or spatiotemporal adaptations underlie the noted improvements in running economy. DESIGN: Cross-sectional. METHODS: Fifteen trained runners (11 males and 4 females) ran three 15-minute trials with 30% bodyweight support at 70% of the speed that elicited their peak oxygen consumption while running on a standard treadmill. A series of 1-way analyses of variance with repeated measures were used to explore differences in dependent variables over the 45 minutes of running. Dependent variables included oxygen consumption, root-mean-square electromyography of the vastus medialis and medial gastrocnemius during stance, and spatiotemporal parameters. RESULTS: Oxygen consumption decreased after the initial exposure, with no further reductions after 20 minutes. Root-mean-square electromyography of the vastus medialis and medial gastrocnemius also decreased over time, with no further reductions after 20 and 10 minutes, respectively. No differences in spatiotemporal parameters were found. CONCLUSIONS: Future research should provide sufficient time for runners to develop a more economical gait pattern prior to collecting dependent variables, and previous findings using lower body positive pressure treadmills may need to be reconsidered. Athletes using these devices for training or rehabilitation should note that increased economy will lower the intensity of a given treadmill setting over time.

Is What You See What You Get? Perceptions of Personal Trainers' Competence, Knowledge, and Preferred Sex of Personal Trainer Relative to Physique.

ABSTRACT: Boerner, PR, Polasek, KM, True, L, Lind, E, and Hendrick, JL. Is what you see what you get? Perceptions of personal trainers' competence, knowledge, and preferred sex of personal trainer relative to physique. J Strength Cond Res 35(7): 1949-1955, 2021-The role that a personal trainer's (PT) physique plays in how potential clients perceive the PT is an understudied, yet potentially powerful, area of inquiry that has important professional implications. The purpose of this study was to investigate how a PT's physique could influence perceptions of his/her (a) PT competence, (b) level of personal training knowledge, and (c) preferred sex of the PT. Subjects (n = 191) were presented with pictures of male and female volunteers labeled as PTs. The pictures emphasized physique and consisted of varying body types (ectomorph, mesomorph, and endomorph) and muscularity (muscular vs. nonmuscular). Subjects examined pictures to answer surveys to rate trainers' competence, knowledge, and preferred sex of PT. Personal trainer physique significantly influenced individuals' perceptions of trainer characteristics. Both mesomorphic and ectomorphic body types were rated as more competent than an endomorphic body type. Muscular PTs were perceived to be significantly more knowledgeable and competent than their nonmuscular peers. Female PTs were perceived as more competent and knowledgeable than male PTs. Findings also suggested many more males preferred to work with a male PT while females lacked consensus. Collectively, PT physique seems to have a profound influence whether they are approached or avoided. These findings may have implications for how PTs market themselves to potential clients.

Differences in associations of product- and process-oriented motor competence assessments with physical activity in children.

There is a positive association between motor competence and physical activity in child populations. Little is known about the relative variance explained in physical activity when process- versus product-oriented approaches are used for evaluating motor competence. This study aimed to examine associations between product- and process-oriented motor competence assessments and their capability to explain variance in physical activity. Participants included 167 children between the ages of 6-9 years. The run, jump, throw and kick were assessed using process-oriented (Test of Gross Motor Development-2nd edition) and product-oriented (run time, jump distance, throw and kick speed) assessments. Physical activity was assessed via Yamax Digi-walker NL2000 pedometers. Weak to strong correlations between process and product assessments were found (range: r = ± 0.01 to ±0.81). Statistically significant correlations between process and product scores were more frequent for the kick and throw. Both product- and process-oriented assessments were poor at explaining variance in pedometer assessed physical activity. No more than 4% of variance in physical activity could be explained by a single skill, regardless of whether product or process scores were used. Continued examination of associations between process- and product-oriented assessments may provide a more holistic understanding of motor competence across developmental time.

Validity and reliability evidence for motor competence assessments in children and adolescents: A systematic review.

Valid and reliable tests of motor competence are necessary to allow researchers and practitioners to quantify levels of motor competence, identify skill deficiencies, and determine the effectiveness of motor skill interventions. The primary study aim was to systematically review the validity and reliability of scores derived from gross motor competence tests for typically developing child and adolescent populations. The secondary aim of this review was to identify the most prevalent motor skills assessed across all instruments. A search of seven electronic databases identified 57 different skill assessment tools from 107 studies. Construct validity was the most common measurement property examined (60 studies; 56%). Content validity (21 studies; 20%) was the least commonly explored measurement property. Scores derived from the Test of Gross Motor Development - second and third edition had the most support for validity and reliability. The most common skills included in these skill batteries were the overhand throw (n = 33), catch (n = 32), jump (n = 31) and hop (n = 26). Research efforts should focus on: (1) further investigation of measurement properties of existing tools rather than developing new assessments and (2) further investigation of existing tools and their measurement properties in adolescent populations.

Concurrent validity and test-retest reliability of Squegg™ - smart dynamometer and handgrip trainer in healthy individuals.

Introduction: Handgrip strength is crucial for overall health and is often evaluated using hand dynamometers. Two hand dynamometers were used in the study: the Jamar® Hydraulic Hand Dynamometer and Squegg™ Smart Dynamometer and Handgrip Trainer, which is a relatively new, Bluetooth-enabled device to measure handgrip strength. The purpose of the study was to compare Jamar and Squegg to determine concurrent validity and, separately, test-retest reliability of Squegg. Methods: The cross-sectional study measured bimanual handgrip strength using the Jamar and Squegg in two sessions, following standard protocols. Participants were 18+ years old, with no hand disease or dysfunction. Spearman's rank correlations were used to evaluate concurrent validity between Jamar and Squegg. Test-retest reliability was evaluated with intraclass correlation coefficient (ICC) estimates and 95% confidence intervals calculated using a mean-rating (k = 2) absolute agreement, 2-way mixed effects model. Results: Data from 594 participants were used to evaluate concurrent validity. Moderately strong correlations between Jamar and Squegg values for the right hand (RH) (ρ = 0.670; p = .001) and Jamar and Squegg values for the left hand (LH) (ρ = 0.730; p = .001) were found, indicating 'good' concurrent validity. Test-retest reliability for Squegg ranged from good to excellent (RH, ICC = 0.911, 95% CI (0.895, 0.924), p = .001; LH, ICC = 0.928, 95% CI (0.915, 0.939), p = .001). Discussion: The Squegg demonstrated good concurrent validity with Jamar and good-to-excellent test-retest reliability. It can be recommended as an alternative to the Jamar as a handgrip strength measurement tool. Squegg, which uses Bluetooth technology, is a reliable and cost-effective option for consistent handgrip strength testing.

Improving Body Mass Index of School-Aged Children Using a Nine-Week Rope Skipping Training Intervention: A One-Group Pre-Test Post-Test Design.

Studies examining the effectiveness of rope skipping training to improve the body mass index (BMI) of school children are scarce. Hence, this study examined the effectiveness of nine-week skipping training on the BMI of primary six school-aged children (n = 77). The participants underwent 30 min of skipping training three days per week over a nine-week period. The participants' BMI was measured at the baseline and during weeks 3, 6 and 9. The results from a one-way ANOVA with repeated measures indicated a statistically significant difference in the BMI for both males [F(3,111) = 9.42, p < 0.001, ηp2 = 0.203] and females [F(3,114) = 7.35, p < 0.001, ηp2 = 0.162], suggesting an improvement in BMI. Post hoc comparisons with a Bonferroni adjustment revealed significant differences in BMI after nine weeks of intervention for males between the pre-test (M = 21.47, SD = 4.94) and the 9-week post-test (M = 20.15, SD = 4.36), and for females between the pre-test (M = 21.56, SD = 5.80) and the 9-week post-test (M = 20.68, SD = 5.32). This study demonstrated that regular participation in vigorous physical activity such as skipping training could promote child health by preventing the likelihood of young children being overweight. This result has implications for the inclusion of skipping training into the school life of school-aged children to help manage their BMI levels.

Relationships among Actual Motor Competence, Perceived Motor Competence, and Health-Related Fitness in College-Aged Males.

Actual motor competence (MC), perceived motor competence (PMC), and health-related fitness (HRF) exhibit a dynamic and reciprocal relationship in child populations, but little is known about the nature of these relationships in young adulthood. The purpose of the study was to assess these relationships in a sample of college-aged males. A total of 55 participants enrolled in an undergraduate Kinesiology course completed the study. Perceived motor competence (PMC) was assessed with the Physical Self-Perception Profile questionnaire; MC was assessed using maximum throw and kick speed and maximum jump distance; HRF was assessed with a two-minute push-up test, two-minute sit-up test, and the Multistage 20-m Shuttle Run Test. Pearson's bivariate correlations were calculated to assess relationships among PMC total score, MC scores, and HRF scores. Two separate indices were calculated to create composite total MC and total HRF scores used for subsequent analyses. Significant correlations were found between PMC total score, MC index, and HRF index. Multiple linear regressions were used for analyzing predictive measures for HRF and PMC scores. From the two regression models, significance varied among total MC scores, PMC scores, and HRF individual measures. These findings may suggest that relationships among MC, HRF, and PMC strengthen over developmental time in young adult males.

Reconceptualizing and Operationalizing Seefeldt's Proficiency Barrier: Applications and Future Directions.

In 1980, Seefeldt introduced the concept of a motor skill "proficiency barrier" that provides a conceptual basis for understanding the importance of a motor skill barrier as it relates to critical public health initiatives. While the intent of Seefeldt's proficiency barrier hypothesis had great potential to advance the field of motor development, the notion of a proficiency barrier was not empirically tested. Instead, this concept lay dormant for several decades. The purpose of this paper was to expand upon Seefeldt's proficiency barrier concept in greater detail by addressing the following questions: (1) what constitutes a motor proficiency barrier? (2) how do we assess/measure the existence of a proficiency barrier? and (3) how do we break through the proficiency barrier in order to maximize the likelihood of participation in health-enhancing levels of physical activity later on in life? We conclude with a future research suggestion to explore the existence of the proficiency barrier.

A Narrative Review of Motor Competence in Children and Adolescents: What We Know and What We Need to Find Out.

Lack of physical activity is a global public health problem causing not only morbidity and premature mortality, but it is also a major economic burden worldwide. One of the cornerstones of a physically active lifestyle is Motor Competence (MC). MC is a complex biocultural attribute and therefore, its study requires a multi-sectoral, multi-, inter- and transdisciplinary approach. MC is a growing area of research, especially in children and adolescents due to its positive association with a plethora of health and developmental outcomes. Many questions, however, remain to be answered in this field of research, with regard to: (i) Health and Developmental-related Associations of MC; (ii) Assessment of MC; (iii) Prevalence and Trends of MC; (iv) Correlates and Determinants of MC; (v) MC Interventions, and (vi) Translating MC Research into Practice and Policy. This paper presents a narrative review of the literature, summarizing current knowledge, identifying key research gaps and presenting questions for future investigation on MC in children and adolescents. This is a collaborative effort from the International Motor Competence Network (IMCNetwork) a network of academics and researchers aiming to promote international collaborative research and knowledge translation in the expansive field of MC. The knowledge and deliverables generated by addressing and answering the aforementioned research questions on MC presented in this review have the potential to shape the ways in which researchers and practitioners promote MC and physical activity in children and adolescents across the world.

Motor competence and health-related fitness in children: A cross-cultural comparison between Portugal and the United States.

BACKGROUND: Motor competence and health-related fitness are important components for the development and maintenance of a healthy lifestyle in children. This study examined cross-cultural performances on motor competence and health-related fitness between Portuguese and U.S. children. METHODS: Portuguese (n = 508; 10.14 ± 2.13 years , mean ± SD) and U.S. (n = 710; 9.48 ± 1.62 years) children performed tests of cardiorespiratory fitness (Progressive Aerobic Cardiovascular Endurance Run), upper body strength (handgrip), locomotor skill performance (standing long jump), and object projection skill performance (throwing and kicking). Portuguese and U.S. children were divided into 2 age groups (6-9 and 10-13 years) for data analysis purposes. A two-factor one-way analysis of covariance (ANOVA) was conducted with the Progressive Aerobic Cardiovascular Endurance Run, handgrip, standing long jump scores, kicking, and throwing speed (km/h) as dependent variables. RESULTS: Results indicated that Portuguese children, irrespective of sex, presented better performances in locomotor and cardiorespiratory performance (standing long jump and Progressive Aerobic Cardiovascular Endurance Run) than U.S. children in both age bands. U.S. children outperformed Portuguese children during throwing and handgrip tests. Kicking tests presented gender differences: Portuguese boys and U.S. girls outperformed their internationally matched counterparts. CONCLUSION: Cultural differences in physical education curricula and sports participation may impact differences in motor competence and fitness development in these countries.

Identifying a motor proficiency barrier for meeting physical activity guidelines in children.

OBJECTIVES: This study examined the existence of a threshold level (proficiency barrier) of actual motor competence (MC) below which a child is not likely to attain 60min of moderate-to-vigorous physical activity (MVPA) per day. DESIGN: A cross-sectional study. METHODS: Actual MC was assessed in 326 children (48.5% boys; age=9.50±1.24years) using the Test of Gross Motor Development-2; MVPA was measured with ActiGraph GT3X+accelerometers. Perceived MC, included as a potential mediating variable, was assessed with the Self-Perception Profile for Children. Binary logistic (mediation) regression analyses controlling for sex and a chi-squared test were used to gain insight into the relationship between (the levels of) actual MC and the percentage of children meeting the MVPA guideline. RESULTS: Actual MC significantly predicted the percentage of children meeting the guideline (B=.03, SE=.01, p<.001), even when controlling for sex. Perceived MC did not mediate this relationship. Children with high actual MC (65-100 percentile) were 2.46 (p=.003) times more likely to meet the guideline than children with low actual MC (0-27 percentile). CONCLUSIONS: The present study demonstrates the potential impact of low MC on children's MVPA levels and suggests evidence for the existence of a proficiency barrier for meeting MVPA guidelines. Almost 90% of the children whose actual MC is below the 'average' threshold do not meet the MVPA guideline. As more children with higher levels of actual MC meet the guideline than their less competent peers, it is crucial to provide opportunities to sufficiently develop children's actual MC.

Run Economy on a Normal and Lower Body Positive Pressure Treadmill.

Lower body positive pressure (LBPP) treadmill running is used more frequently in clinical and athletic settings. Accurate caloric expenditure is required for proper exercise prescription, especially for obese patients performing LBPP exercise. It is unclear if running on LBPP changes running economy (RE) in proportion to the changes in body weight. The purpose of the study was to measure the oxygen consumption (VO2) and running economy (RE) of treadmill running at normal body weight and on LBPP. Twenty-three active, non-obese participants (25.8±7.2 years; BMI = 25.52±3.29 kg·m-2) completed two bouts of running exercise in a counterbalanced manner: (a) on a normal treadmill (NT) and (b) on a LBPP treadmill at 60% (40% of body weight supported) for 4 min at 2.24 (5 mph), 2.68 (6 mph), and 3.13 m·s-1 (7 mph). Repeated measures ANOVA showed a statistically significant interaction in RE among trials, F(2, 44) = 6.510, p <.0005, partial η2 = 0.228. An examination of pairwise comparisons indicated that RE was significantly greater for LBPP across the three speeds (p < 0.005). As expected, LBPP treadmill running resulted in significantly lower oxygen consumption at all three running speeds. We conclude that RE (ml O2·kg-1·km-1) of LBPP running is significantly poorer than normal treadmill running, and the ~30% change in absolute energy cost is not as great as predicted by the change in body weight (40%).

Four Weeks of Off-Season Training Improves Peak Oxygen Consumption in Female Field Hockey Players.

The purpose of the study was to examine the changes in peak oxygen consumption ( V ˙O2peak) and running economy (RE) following four-weeks of high intensity training and concurrent strength and conditioning during the off-season in collegiate female field hockey players. Fourteen female student-athletes (age 19.29 ± 0.91 years) were divided into two training groups, matched from baseline V ˙O2peak: High Intensity Training (HITrun; n = 8) and High Intensity Interval Training (HIIT; n = 6). Participants completed 12 training sessions. HITrun consisted of 30 min of high-intensity running, while HIIT consisted of a series of whole-body high intensity Tabata-style intervals (75⁻85% of age predicted maximum heart rate) for a total of four minutes. In addition to the interval training, the off-season training included six resistance training sessions, three team practices, and concluded with a team scrimmage. V ˙O2peak was measured pre- and post-training to determine the effectiveness of the training program. A two-way mixed (group × time) ANOVA showed a main effect of time with a statistically significant difference in V ˙O2peak from pre- to post-testing, F(1, 12) = 12.657, p = 0.004, partial η² = 0.041. Average (±SD) V ˙O2peak increased from 44.64 ± 3.74 to 47.35 ± 3.16 mL·kg-1·min-1 for HIIT group and increased from 45.39 ± 2.80 to 48.22 ± 2.42 mL·kg-1·min-1 for HITrun group. Given the similar improvement in aerobic power, coaches and training staff may find the time saving element of HIIT-type conditioning programs attractive.

Motor competence and characteristics within the preschool environment.

OBJECTIVES: Environmental characteristics within preschools that influence children's motor competence are largely unknown. The purpose of the present study was to examine the contribution of various preschool environmental characteristics to children's locomotor, object control, and total gross motor scores. DESIGN: Cross-sectional, observational study of 3-5 year-old children (n=229) from 22 preschools in South Carolina. METHODS: The Children's Activity and Movement in Preschool Study (CHAMPS) Motor Skills Protocol assessed MC. Preschool directors provided information regarding policies and practices. The research team measured playgrounds and classrooms, and the Early Childhood Environment Rating Scale-Revised assessed preschool quality. Time spent in open space and electronic media use were also assessed using direct observation. The aforementioned variables predicted children's object control, locomotor, and total gross motor scores. RESULTS: Classroom size/child ratio, teacher education, playground size, electronic media use, and trips to outside organizations emerged as significant predictors of locomotor score and total motor score. The object control model was non-significant. CONCLUSIONS: Preschools may be able to promote motor competence by allowing children more time in open spaces, structured activity experiences, and by expanding existing outdoor playground space whenever possible.

Associations among Elementary School Children's Actual Motor Competence, Perceived Motor Competence, Physical Activity and BMI: A Cross-Sectional Study.

BACKGROUND: Positive associations between motor competence and physical activity have been identified by means of variable-centered analyses. To expand the understanding of these associations, this study used a person-centered approach to investigate whether different combinations (i.e., profiles) of actual and perceived motor competence exist (aim 1); and to examine differences in physical activity levels (aim 2) and weight status (aim 3) among children with different motor competence-based profiles. MATERIALS AND METHODS: Children's (N = 361; 180 boys = 50%; Mage = 9.50±1.24yrs) actual motor competence was measured with the Test of Gross Motor Development-2 and their perceived motor competence via the Self Perception Profile for Children. We assessed physical activity via accelerometers; height through stadiometers, and weight through scales. Cluster analyses (aim 1) and MANCOVAs (aim 2 & 3) were used to analyze the data. RESULTS: The analysis generated two predictable groups: one group displaying relatively high levels of both actual (M TGMD-2 percentile = 42.54, SD = 2.33) and perceived motor competence (M = 3.42, SD = .37; high-high), and one group with relatively low levels of both (M percentile = 9.71, SD = 3.21; M PMC = 2.52, SD = .35; low-low). One additional group was also identified as having relatively low levels of actual motor competence (M percentile = 4.22, SD = 2.85) but relatively high levels of perceived motor competence (M = 3.52, SD = .30; low-high). The high-high group demonstrated higher daily physical activity (M = 48.39±2.03) and lower BMI (M = 18.13±.43) than the low-low group (MMVPA = 37.93±2.01; MBMI = 20.22±.42). The low-high group had similar physical activity-levels as the low-low group (M = 36.21±2.18) and did not significantly differ in BMI (M = 19.49±.46) from the other two groups. CONCLUSIONS: A combination of high actual and perceived motor competence is related to higher physical activity and lower weight status. It is thus recommended to expand health interventions in children with components that foster the development of both actual and perceived motor competence. Health professionals should furthermore pay sufficient attention to endorsing children's actual and perceived motor competence.

Associations among selected motor skills and health-related fitness: indirect evidence for Seefeldt's proficiency barrier in young adults?

PURPOSE: This exploratory study examined the notion of Seefeldt's (1980) hypothesized motor skill "proficiency barrier" related to composite levels of health-related physical fitness (HRF) in young adults. METHOD: A motor skill competence (MSC) index composed of maximum throwing and kicking speed and jumping distance in 187 young adults aged 18 to 25 years old was evaluated against a composite index of 5 health-related fitness (HRF) test scores. MSC (high, moderate, and low) and HRF indexes (good, fair, and poor) were categorized according to normative fitness percentile ranges. 2 separate 3-way chi-square analyses were conducted to determine the probabilities of skill predicting fitness and fitness predicting skill. RESULTS: Most correlations among HRF and MSC variables by gender demonstrated low-to-moderate positive correlations in both men (12/15; r = .23-.58) and women (14/15; r = .21-.53). Chi-square analyses for the total sample, using composite indexes, demonstrated statistically significant predictive models, chi2(1, N = 187) = 66.99, p < .001, Cramer's V = .42. Only 3.1% of low-skilled (2 of 65) individuals were classified as having a "good" HRF. Only 1 participant (out of 65) who demonstrated high MSC was classified as having "poor" HRF (1.5%). CONCLUSION: Although individual correlations among individual MSC and HRF measures were low to moderate, these data provide indirect evidence for the possibility of a motor skill "proficiency barrier" as indicated by low composite HRF levels. This study may generate future research to address the proficiency barrier hypothesis in youth as well as adults.