New Insight For Activity Intensity Relativity: Metabolic Expenditure During Object Projection Skill Performance

This dissertation consist of four studies that examine energy expenditure (EE) during object projection skill performance (OPSP). These four studies have the potential to inform physical education (PE) curricula and physical activity (PA) interventions by providing an understanding the acute EE associated with performing OPSP in developmentally appropriate activities. If OPSP is associated with high EE, then promoting their development during physical activity interventions and physical education (PE) will have both an acute and long-term health-enhancing benefit. Thus, the purposes of these four studies was to examine adult and children’s EE associated with the performance of object projection skills at different intensity intervals. The purpose of Study 1 was to examine the metabolic cost (METS) of performing object projection skills at three practice trial intervals (6, 12 and 30 seconds). 40 adults (female n = 20) aged 18-30 (M = 23.7 ± 2.9 years) completed three, nine-minute sessions of skill trials performed at 6, 12, and 30 second intervals. Participants performed kicking, throwing and striking trials in a blocked schedule with maximal effort. Average METS during each session were measured using a COSMED K4b2. A three (interval condition) X two (sex) ANOVA was conducted to examine differences in METS across interval conditions and by sex. Data indicated a main effect for interval condition (df = 5,114, F = 187.02, p \u3c .001, η2 = 0.76) with decreased interval times yielding significantly higher METS [30 sec = 3.45, 12 sec = 5.68, 6 sec = 8.21]. A main effect for sex (df = 5, 114, F = 35.39, p \u3c .001, η2 = 0.24) also was found with men demonstrating higher METS across all intervals. At a rate of only two trials/min, participants elicited moderate physical activity, with 12 and 6 second intervals exhibiting vigorous PA. The purpose of Study 2 was to compare the EE levels during OPSP as assessed by indirect calorimetry and accelerometry. Thirty-four adults (female n = 18) aged 18-30 (23.5 ± 2.5 years) performed three, nine-minute sessions of kicking, over-arm throwing, and striking performed at 6, 12, and 30 second intervals. EE was estimated (METS) using indirect calorimetry (COSMED k4b2) and hip-worn accelerometry (ActiGraph GT3X+). EE using indirect calorimetry demonstrated moderate-intensity physical activity (PA) (3.4 ± 0.7 METS – 30sec interval, 5.8 ± 1.2 METS – 12sec interval) to vigorous intensity PA (8.3 ± 1.7 METS – 6sec interval). However, accelerometry predicted EE suggested only light-intensity PA (1.7 ± 0.2 METS – 30sec interval, 2.2 ± 0.4 METS – 12sec interval, 2.7 ± 0.6 METS – 6sec interval). Accelerometry does not adequately capture the PA intensity level when performing OPSP skills, regardless of differences in performance intervals. The purpose of Study 3 was to examine boys and girls EE during OPSP at three different intensity intervals. Children (42, Mage = 8.1) participated in a within-subjects design with three nine-minute sessions of trial intervals (i.e., 6, 12, and 30 second intervals) where participants performed kicking, throwing, and striking. Skills were performed with maximum effort in blocks of five trials of each skill in serial order until each nine-minute interval session was completed. The average metabolic equivalent of task (METS) during minutes 4-8 of each nine-minute session were calculated using a COSMED K4b2 portable gas analyzer. A 3 (interval condition) X2 (sex) ANOVA was conducted to examine differences in average METS across groups and sex. Data indicated a main effect for interval condition (df = 2, 123, F = 94.36, p \u3c .001, η2 = 0.605). Post hoc t-tests demonstrated decreasing performance interval times yielded significantly (p \u3c .001) and progressively higher metabolic expenditure across the three conditions (30 sec = 4.5 ± 0.8 METS, 12 sec = 6.3 ± 1.3), 6 sec = 8.3 ± 1.6). There also was a main effect for sex (df = 1, 120, F = 52.28, p \u3c .001 η2 = 0.305). Boys demonstrated higher METS at each performance interval (p \u3c .001). Average METS for boys and girls respectively were 9.3 (± 1.4) and 7.2 (± 1.2). METS during the six second intervals, 7.0 (± 1.1) and 5.6 (± 1.1) METS during 12 second intervals and 4.8 (± 0.7) and 4.1 (± 0.7) during 30 second intervals. Results indicate skill practice with a maximum of one trial every 30 seconds resulted in the equivalent of at least moderate physical activity (\u3e 4.0 METS) and intervals of 6 seconds demonstrated vigorous physical activity (\u3e 7.0 METS). These data indicate practicing/performing object projection skills, even at intervals that allow for instruction and feedback, (1 trial/30sec) is equivalent to MVPA levels in children. The purpose of Study 4 was to compare the EE levels during OPSP as assessed by hip- and wrist-worn accelerometry in children (7-9 years). Forty-two children (female n = 20, Mage = 8.1 ± 0.8 years) performed three, nine-minute sessions of kicking, over-arm throwing, and striking at performance intervals 0f 6, 12, and 30 seconds. EE was estimated METS using indirect calorimetry (COSMED k4b2) and accelerometers (ActiGraph GT3X+) worn on three different locations (hip, dominant wrist, and non-dominant-wrists). EE using indirect calorimetry demonstrated moderate-intensity physical activity (PA; 4.5 ± 0.8 METS – 30sec interval, 6.3 ± 1.3 METS – 12sec interval) to vigorous intensity PA (8.3 ± 1.7 METS – 6sec interval). However, hip-worn accelerometry predicted EE suggested only light-intensity PA (2.4 ± 0.2 METS – 30sec interval, 2.8 ± 0.5 METS – 12sec interval, 3.4 ± 0.7 METS – 6sec interval) dominant wrist-worn accelerometry predicted EE suggested only light-intensity PA (2.8 ± 0.8 METS – 30sec interval, 3.9 ± 0.6 METS – 12sec interval, 5.2 ± 0.9 METS – 6sec interval). Accelerometry does not accurately categorize the physical activity intensity level when performing OPSP skills, regardless of differences in performance intervals or accelerometer wear location in children. These data have the potential to significantly impact physical activity intervention strategies and the implementation of PE curricula attempting to promote moderate to vigorous PA by informing specific trial intervals which promote health-enhancing physical activity levels (i.e., MVPA). Information gleaned from this study provides evidence that the practice of OPSP can aid in the achievement (acute) of recommended health-enhancing levels of EE (i.e., MVPA), as well as promote a foundation for skill development that promotes lifelong physical activity

Calibration and Cross-Validation of Accelerometery for Estimating Movement Skills in Children Aged 8-12 Years

This study sought to calibrate triaxial accelerometery, worn on both wrists, waist and both ankles, during children’s physical activity (PA), with particular attention to object control motor skills performed at a fast and slow cadence, and to cross-validate the accelerometer cut-points derived from the calibration using an independent dataset. Twenty boys (10.1 ±1.5 years) undertook seven, five-minute bouts of activity lying supine, standing, running (4.5kmph−1) instep passing a football (fast and slow cadence), dribbling a football (fast and slow cadence), whilst wearing five GENEActiv accelerometers on their non-dominant and dominant wrists and ankles and waist. VO2 was assessed concurrently using indirect calorimetry. ROC curve analysis was used to generate cut-points representing sedentary, light and moderate PA. The cut-points were then cross-validated using independent data from 30 children (9.4 ± 1.4 years), who had undertaken similar activities whilst wearing accelerometers and being assessed for VO2. GENEActiv monitors were able to discriminate sedentary activity to an excellent level irrespective of wear location. For moderate PA, discrimination of activity was considered good for monitors placed on the dominant wrist, waist, non-dominant and dominant ankles but fair for the non-dominant wrist. Applying the cut-points to the cross-validation sample indicated that cut-points validated in the calibration were able to successfully discriminate sedentary behaviour and moderate PA to an excellent standard and light PA to a fair standard. Cut-points derived from this calibration demonstrate an excellent ability to discriminate children’s sedentary behaviour and moderate intensity PA comprising motor skill activity.N/

Risk factors associated with non-contact anterior cruciate ligament injury: a systematic review

Background: With the increasing number of individuals participating in sports every year, injury - specifically anterior cruciate ligament (ACL) injury - remains an inherent risk factor for participants. The majority of ACL injuries occur from a non-contact mechanism, and there is a high physical and financial burden associated with injury. Understanding the risk factors for ACL injury may aid in the development of prevention efforts. Purpose: The purpose of this review was to synthesize and appraise existing literature for risk factors associated with non-contact anterior cruciate ligament (ACL) injury in both sexes. Study Design: Systematic review. Methods: An electronic literature search was conducted utilizing the MEDLINE database and The Cochrane library for articles available through February 2016. All titles and abstracts were reviewed and full text articles meeting eligibility criteria were assessed in detail to determine inclusion or exclusion. Articles reviewed in full text were reviewed for scientific evidence of risk factors for ACL injury. Results from studies were extracted and initially classified as either intrinsic or extrinsic risk factors, and then further categorized based upon the evidence presented in the studies meeting inclusion criteria. Data extracted from eligible studies included general study characteristics (study design, sample characteristics), methodology, and results for risk factors included. Results: Principal findings of this systematic review identified the following risk factors for ACL injury in both sexes: degrading weather conditions, decreased intercondylar notch index or width, increased lateral or posterior tibial plateau slope, decreased core and hip strength, and potential genetic influence. Conclusions: Neuromuscular and biomechanical risk factors may be addressed through neuromuscular preventative training programs. Though some extrinsic and other inherent physiological factors tend to be non-modifiable, attempts to improve upon those modifiable factors may lead to a decreased incidence of ACL injury. Level of Evidence: 2a. Key Words: anterior cruciate ligament, ACL, risk factor, injury, rupture

Comparison of Indirect Calorimetry- and Accelerometry-Based Energy Expenditure During Children‘s Discrete Skill Performance

To compare children’s energy expenditure (EE) levels during object projection skill performance (OPSP; e.g., kicking, throwing, striking) as assessed by hip- and wrist-worn accelerometers. Method: Forty-two children (female n = 20, Mage = 8.1 ± 0.8 years) performed three, nine-minute sessions of kicking, over-arm throwing, and striking at performance intervals of 6, 12, and 30 seconds. EE was estimated using indirect calorimetry (COSMED k4b2) and accelerometers (ActiGraph GT3X+) worn on three different locations (hip, dominant-wrist, and non-dominant-wrist) using four commonly used cut-points. Bland-Altman plots were used to analyze the agreement in EE estimations between accelerometry and indirect calorimetry (METS). Chi-square goodness of fit tests were used to examine the agreement between accelerometry and indirect calorimetry. Results: Hip- and wrist-worn accelerometers underestimated EE, compared to indirect calorimetry, during all performance conditions. Skill practice at a rate of two trials per minute resulted in the equivalent of moderate PA and five trials per minute resulted in vigorous PA (as measured by indirect calorimetry), yet was only categorized as light and/or moderate activity by all measured forms of accelerometry. Conclusion: This is one of the first studies to evaluate the ability of hip- and wrist-worn accelerometers to predict PA intensity levels during OPSP in children. These data may significantly impact PA intervention measurement strategies by revealing the lack of validity in accelerometers to accurately predict PA levels during OPSP 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 Endur ance 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 outper formed 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.4811-99FE-2ECD | Luis Paulo RodriguesN/

The association between the functional movement screen (tm), y-balance test, and physical performance tests in male and female high school athletes

Background: Poor balance, lack of neuromuscular control, and movement ability are predictors of performance and injury risk in sports and physical activity participation. The Functional Movement Screen™ (FMS™) and lower quarter Y-Balance Test (YBT) have been used by clinicians to evaluate balance, functional symmetry, and static and dynamic movement patterns, yet little information exists regarding the relationship between the FMS™, YBT, and physical performance tests (e.g. vertical jump) within the high school population. Purpose: The purpose of this study was to investigate the relationship between the FMSTM, dynamic balance as measured by the YBT and physical performance tests (standing long jump, vertical jump, Pro Agility Test) in male and female high school athletes. Study Design: Cohort study. Methods: Fifty-six high school athletes (28 females, 28 males; mean age 16.4 ± 0.1) who participated in organized team sports were tested. Participants performed the FMS™, YBT, and three physical performance tests (standing long jump, vertical jump, Pro Agility Test). Results: Females outperformed males on the FMS™ and YBT, while males outperformed females on the performance tests. In both sexes, the composite FMSTM score was positively correlated with the left and composite YBT scores. Agility was negatively correlated with composite FMSTM in males (p < 0.05) and the left and composite YBT in females (p < 0.05). Conclusions: The FMST M and YBT may evaluate similar underlying constructs in high school athletes, such as dynamic balance and lower extremity power. The results of this study demonstrate the utility of the FMS and YBT to relate multiple constructs of muscular power to an individual’s ability to balance. Furthermore, establishing the need for the utilization and application of multiple field-based tests by sports medicine professionals and strength and conditioning coaches when evaluating an athlete’s movement and physical performance capabilities. Utilization of multiple field-based tests may provide the first step for the development of injury prevention strategies and long-term athlete development programs

Fit to Play? Health-Related Fitness Levels of Youth Athletes: A Pilot Study

A recent National Strength and Conditioning Association position statement suggests that many youth are not prepared for the physical demands of sport. The purpose of this study was to compare health-related fitness (HRF) of youth athletes with normative findings from the general population. We recruited 136 athletes (63 male and 73 female athletes) aged 11-19 (16.01 ± 1.35) years and collected HRF (body composition, cardiorespiratory endurance, musculoskeletal strength and endurance). Results were categorized based on FITNESSGRAM® standards and compared with Canadian youth general population normative data. Most male athletes were classified as "needs improvement" for cardiorespiratory and muscular endurance, and body mass index (BMI). Conversely, most female athletes were at or above the "healthy fitness zone" for all measures. Male athletes at both age groups (11-14, 15-19; p < 0.001) and female athletes aged 11-14 (p < 0.05) demonstrated lower cardiorespiratory endurance compared with Canadian general population. Female athletes (both age groups) demonstrated greater muscular strength, and male athletes (age, 15-19 years) demonstrated lower BMI than the Canadian general population. The results are concerning as male athletes demonstrated poorer HRF compared with the general population. Although most female athletes were within healthy ranges, a portion of them were still at risk. Considering the demands sport places on the body, evaluating HRF is paramount for performance and injury prevention but more importantly for overall health. Youth sport and strength coaches should evaluate and aim to enhance HRF, as participation in sport does not guarantee adequate HRF. Promoting long-term athletic development and life-long health should be a priority in youth

Functional Movement Screen(TM) in Youth Sport Participants: Evaluating the Proficiency Barrier for Injury

Background & Purpose: The number of youth participating in sport increases yearly; however, the evaluation of youths’ movement ability and preparedness for sport remains inadequate or neglected. The Functional Movement Screen (FMS™) is an assessment of an individual’s movement quality that has been utilized to evaluate risk of injury in collegiate and professional sport; however, there is minimal support regarding the predictive value of the screen in youth sport. The purpose of this study was to evaluate the mean and distribution of FMS™ performance in sport participants age 11-18, and to evaluate the existence of a composite FMS™ score proficiency barrier to predict injury risk. Study Design: Prospective cohort study. Methods: One hundred, thirty-six participants (63 male, 73 female) age 11 to 18 years (16.01 + 1.35) were recruited from local schools and sport organizations. The FMS™ was administered prior to each participant’s competitive season and scored by researchers who demonstrated reliability in assessments derived from the screen (κw = 0.70 to 1). Injury data were collected by the participants’ Athletic Trainer over one season. An injury was defined as any physical insult or harm resulting from sports participation that required an evaluation from a health professional with time modified or time lost from sport participation. Results: Females scored significantly higher than males for mean FMS™ composite score (t=14.40; m=12.62; p < 0.001), and on individual measures including: the hurdle step (t=1.91; m=1.65; p < 0.001), shoulder mobility (t=2.68; m=2.02; p < 0.001), active straight leg raise (t=2.32; m=1.87; p < 0.001), and the rotary stability components (t=1.91; m=1.65; p < 0.05). Two FMS™ composite scores (score <14 and <15) significantly increased the odds of injury (OR=2.955). When adjusting for sport, there was no score relating to increased odds of injury. Conclusion: Dysfunctional movement as identified by the FMS™ may be related to increased odds of injury during the competitive season in youth athletes. Consideration of an individual’s movement within the context of their sport is necessary, as each sport and individual have unique characteristics. Addressing movement dysfunction may aid in injury reduction and potentially improve sport performance. Level of Evidence: 1b. Key Words: Functional movement screen, injury prevention, movement system, movement quality, youth spor

Estimating physical activity in children aged 8-11 years using accelerometry: contributions from fundamental movement skills and different accelerometer placements.

Accelerometers are widely used to assess physical activity, but it is unclear how effective accelerometers are in capturing fundamental movement skills in children. This study examined the energy expenditure during different physical activities (PA) and calibrated triaxial accelerometry, worn at the wrist, waist and ankle, during children’s PA with attention to object control movement skills and cycling. Thirty children (14 girls) aged 8 to 11 years wore a GENEActiv accelerometer on their non-dominant wrist, dominant wrist, waist and ankle. Children undertook eight, 5-min bouts of activity comprising being lay supine, playing with Lego, slow walking, medium walking, medium paced running, overarm throwing and catching, instep passing a football and cycling at 35 W. VO2 was assessed concurrently using indirect calorimetry. Indirect calorimetry indicated that being lay supine and playing with Lego were classified as sedentary in nature (3 METs). ROC curve analysis indicated that discrimination of sedentary activity was excellent for all placements although the ankle performed better than other locations. This pattern was replicated for moderate physical activity (MPA) where the ankle performed better than other locations. Data were reanalyzed removing cycling from the data set. When this analysis was undertaken discrimination of sedentary activity remained excellent for all locations. For MPA discrimination of activity was considered good for waist and ankle placement and fair for placement on either wrist. The current study is the first to quantify energy expenditure in object control fundamental movement skills via indirect calorimetry in children aged 8–11 years whilst also calibrating GENEActiv accelerometers worn at four body locations. Results suggest throwing and catching is categorized as light intensity and instep kicking a football moderate intensity, resulting in energy expenditure equivalent to slow or medium paced walking or cycling and running, respectively. Ankle worn accelerometry appears to provide the most suitable wear location to quantify MPA including ambulatory activity, object control skills and cycling, in children aged 8–11 years.N/

The impact of motor competence on energy expenditure during object control skill performance in children and young adults

Background: An understanding of how motor skill performance levels relate to energy expenditure (EE) is an important, yet relatively unexplored topic that may better inform physical activity interventions. Aim: This study examined the impact of motor competence (MC) on EE during the performance of object control skills in children and young adults. Method: Forty-two children (Mage 8.1 years) and 40 young adults (Mage = 23.4 years) completed sessions of throwing and kicking at varying intensity intervals. Polynomial regressions with response surface analysis were conducted to analyze the impact of process- and product-oriented MC levels on EE. Results: Moderate positive associations among process-oriented motor competence levels and EE were demonstrated in all trial interval conditions with stronger associations shown for shorter trial intervals. Conclusion: Individuals' movement quality (process) demonstrated greater associations with EE than performance product (speed), especially with higher intensity skill practice. These results provide additional evidence of the positive impact that MC has on the health benefits of physical activity, specifically during participation in activities that inherently require repeated performance of object control skills