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Paul B. Gastin, Denny Meyer, Emy Huntsman and Jill Cook

Purpose:

To assess the relationships between player characteristics (including age, playing experience, ethnicity, and physical fitness) and in-season injury in elite Australian football.

Design:

Single-cohort, prospective, longitudinal study.

Methods:

Player characteristics (height, body mass, age, experience, ethnicity, playing position), preseason fitness (6-min run, 40-m sprint, 6 × 40-m sprint, vertical jump), and in-season injury data were collected over 4 seasons from 1 professional Australian football club. Data were analyzed for 69 players, for a total of 3879 player rounds and 174 seasons. Injury risk (odds ratio [OR]) and injury severity (matches missed; rate ratio [RR]) were assessed using a series of multilevel univariate and multivariate hierarchical linear models.

Results:

A total of 177 injuries were recorded with 494 matches missed (2.8 ± 3.3 matches/injury). The majority (87%) of injuries affected the lower body, with hamstring (20%) and groin/hip (14%) most prevalent. Nineteen players (28%) suffered recurrent injuries. Injury incidence was increased in players with low body mass (OR = 0.887, P = .005), with poor 6-min-run performance (OR = 0.994, P = .051), and playing as forwards (OR = 2.216, P = .036). Injury severity was increased in players with low body mass (RR = 0.892, P = .008), tall stature (RR = 1.131, P = .002), poor 6-min-run (RR = 0.990, P = .006), and slow 40-m-sprint (RR = 3.963, P = .082) performance.

Conclusions:

The potential to modify intrinsic risk factors is greatest in the preseason period, and improvements in aerobic-running fitness and increased body mass may protect against in-season injury in elite Australian football.

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Thomas W. Buford, Douglas B. Smith, Matthew S. O’Brien, Aric J. Warren and Stephen J. Rossi

Purpose:

The purpose of the present investigation was to examine the physiological response of collegiate wrestlers to their competitive season.

Methods:

Eleven Division I collegiate wrestlers (mean ± SD; 19.45 ± 1.13 y) volunteered and completed 4 testing sessions throughout the course of the collegiate wrestling season. Testing sessions were conducted pre-, mid-, and postseason, as well as before the national tournament. Testing consisted of weigh-in, skinfold body composition testing, and a 50-rep concentric, isokinetic leg extension muscle endurance test (180°/s). Muscular performance variables measured included peak torque, peak torque at fatigue, percent decline, and peak torque/body mass ratio.

Results:

A significant increase (P < .05) of 2.9% was observed for body mass between midseason and postseason (2.38 kg). From pre- to postseason, a mean increase of 3.8% (3.1 kg) was observed for body mass. An increase (P < .05) in BF% of 2.9% was observed between prenationals and postseason. No significant differences (P > .05) were observed between consecutive time points for quadriceps peak torque; however, there was a significant increase (P < .05) between preseason and prenationals (23.39 N·m). Peak torque at fatigue was greater (P < .05) at midseason than preseason, representing an increase of 9.82 N·m. Between midseason and prenationals testing, we observed an 11% increase (P < .05) in %DCLN. Finally, we noted an increase (P < .05) from 0.6 to 0.69 in peak torque/body mass ratio between preseason and prenationals.

Conclusions:

Our results indicate that while force values seem to suffer at midseason, the wrestlers compensated and were strongest just before their national competition.

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Shivam Bhan, Iris Levine and Andrew C. Laing

The biomechanical effectiveness of safety floors has never been assessed during sideways falls with human volunteers. Furthermore, the influence of body mass index (BMI) and gender on the protective capacity of safety floors is unknown. The purpose of this study was to test whether safety floors provide greater impact attenuation compared with traditional flooring, and whether BMI and gender modify their impact attenuation properties. Thirty participants (7 men and 7 women of low BMI; 7 men and 9 women of high BMI) underwent lateral pelvis release trials on 2 common floors and 4 safety floors. As a group, the safety floors reduced peak force (by up to 11.7%), and increased the time to peak force (by up to 25.5%) compared with a traditional institutional grade floor. Force attenuation was significantly higher for the low BMI group, and for males. Force attenuation was greatest for the low BMI males, averaging 26.5% (SD = 3.0) across the safety floors. These findings demonstrate an overall protective effect of safety floors during lateral falls on the pelvis, but also suggest augmented benefits for frail older adults (often with low body mass) who are at an increased risk of hip fracture.

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Cesar Marius Meylan, John Cronin, Will G. Hopkins and Jonathan Oliver

Adjustment for body mass and maturation of strength, power, and velocity measures of young athletes is important for talent development. Seventy-four youth male athletes performed a ballistic leg press test at five loads relative to body mass. The data were analyzed in maturity groups based on years from peak height velocity: −2.5 to −0.9 y (n = 29); −1.0 to 0.4 y (n = 28); and 0.5 to 2.0 y (n = 16). Allometric scaling factors representing percent difference in performance per percent difference in body mass were derived by linear regression of log-transformed variables, which also permitted adjustment of performance for body mass. Standardized differences between groups were assessed via magnitude-based inference. Strength and power measures showed a greater dependency on body mass than velocity-related variables (scaling factors of 0.56–0.85 vs. 0.42–0.14%/%), but even after adjustment for body mass most differences in strength and power were substantial (7–44%). In conclusion, increases in strength and power with maturation are due only partly to increases in body mass. Such increases, along with appropriate adjustment for body mass, need to be taken into account when comparing performance of maturing athletes.

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Samuel N. Cheuvront, Robert Carter III, Scott J. Montain and Michael N. Sawka

The purpose of this study was to quantify the variability and stability of 1st morning body mass (BM) fluctuations during daily exercise in the heat while following traditional fluid intake guidance. Data from 65 men were examined retrospectively. BM fluctuations were monitored over 4 to 15 consecutive days. Group daily variation in BM was 0.51 ± 0.20 kg. Group coefficient of variation was 0.66 ± 0.24%, normally distributed, and not related to either absolute BM (r = 0.04) or number of measurements (r = 0.34). Three days resulted in a similar variability estimate compared to 6 or 9 d, although precision was improved with 9 d. In conclusion, 3 consecutive BM measurements provide an accurate assessment of daily BM variability, which is less than 1% for active men when replacing 100% of sweat losses during exercise. The data also suggest that daily BM is a sufficiently stable physiological parameter for potential daily fluid balance monitoring.

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John T. Foley, Meghann Lloyd and Viviene A. Temple

This study examined temporal trends in body mass index (BMI) among United States adults with intellectual disability (ID) participating in Special Olympics from 2005 to 2010. In addition, the prevalence of obesity was compared with published National Health and Nutrition Examination Survey (NHANES) statistics. After data cleaning, 6,004 height and weight records (male = 57%) were available from the Special Olympics International Healthy Athletes Health Promotion database for the calculation of BMI. Rates of overweight and obesity were very high but generally stable over time. Compared with NHANES statistics, the prevalence of obesity was significantly higher for Special Olympics female participants in each data collection cycle. Integrated efforts to understand the social, environmental, behavioral, and biological determinants of obesity and among Special Olympics participants are needed.

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Eva D’Hondt, Benedicte Deforche, Ilse De Bourdeaudhuij and Matthieu Lenoir

The purpose of this study was to investigate gross and fine motor skill in overweight and obese children compared with normal-weight peers. According to international cut-off points for Body Mass Index (BMI) from Cole et al. (2000), all 117 participants (5–10 year) were classified as being normal-weight, overweight, or obese. Level of motor skill was assessed using the Movement Assessment Battery for Children (MABC). Scores for balance (p < .01) and ball skills (p < .05) were significantly better in normal-weight and overweight children as compared with their obese counterparts. A similar trend was found for manual dexterity (p < .10). This study demonstrates that general motor skill level is lower in obese children than in normal-weight and overweight peers.

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Karen H. Weiller, Allen W. Jackson and Rhonda D. Meyer

Previous research has reported that Hispanic youth were significantly higher in skinfolds and body mass index (BMI) when contrasted to national reference data or comparison groups of white youth. The present study sought to determine the passing percentage for a sample of Hispanic youth for the BMI and the 1-mile run (OMR) using the Fitnessgram standards. The sample included 722 children, ages 7 to 14 years. The Hispanic youth’s passing percentages for the OMR compare favorably with the National Children and Youth Fitness Studies. The BMI results indicate the passing percentages are lower for the Hispanic, which is in agreement with past reports on body composition in Hispanic youth. Using the Fitnessgram standards, these data indicate the cardiovascular endurance of Hispanic youth may be similar to or better than the general population of children in the U.S. A higher rate of unhealthy body composition may be present, which would warrant targeted interventions for Hispanic children.

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Richard Larouche, Meghann Lloyd, Emily Knight and Mark S. Tremblay

The current investigation assessed the impact of active school transportation (AST) on average daily step counts, body mass index (BMI) and waist circumference in 315 children in Grades 4–6 who participated to Cycle 2 of the Canadian Assessment of Physical Literacy (CAPL) pilot testing. T-tests revealed a significant association between AST and lower BMI values (18.7 ± 3.3 vs. 19.9 ± 3.8 kg/m2). The active commuters accumulated an average of 662 more steps per day, and their waist circumference was lower by an average of 3.1 cm, but these differences were not statistically significant. ANCOVA analyses controlling for age and step counts, found trends toward lower BMI and waist circumference values among the active commuters. These results suggest that AST may be a valid strategy to prevent childhood obesity; further research is needed to determine more precisely the impact of AST on body composition, and the direction of the relationship.

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Judith Jiménez, Maria Morera, Walter Salazar and Carl Gabbard

Purpose:

Motor skill competence has been associated with physical activity level, fitness, and other relevant health-related characteristics. Recent research has focused on understanding these relationships in children and adolescents, but little is known about subsequent years. The aim of this study was to examine the relationship between fundamental motor skill (FMS) ability and body mass index (BMI) in young adults.

Method:

Participants, 40 men and 40 women (M age = 19.25 yr, SD = 2.48), were assessed for BMI and motor competence with 10 fundamental motor skills (FMSs) using the Test for Fundamental Motor Skills in Adults (TFMSA).

Results:

BMI was negatively associated with total motor ability (r = –.257; p = .02) and object control skills (r = –.251; p = .02); the relationship with locomotor skills was marginally insignificant (r = –.204; p = .07). In regard to individual skills, a significant negative association was found for running, jumping, striking, and kicking (ps < .05). Multiple regression analysis indicated that BMI and gender predicted 42% of the variance in total FMS score; gender was the only significant predictor.

Conclusion:

Overall, these preliminary findings suggest that young adults with higher FMS ability are more likely to have lower BMI scores.