97 research outputs found
Inter-Investigator Reliability of Anthropometric Prediction of 1RM Bench Press in College Football Players
International Journal of Exercise Science 9(4): 427-436, 2016. The purpose of this study was to determine the effect of inter-investigator differences in anthropometric assessments on the prediction of one-repetition maximum (1RM) bench press in college football players. Division-II players (n = 34, age = 20.4 ± 1.2 y, 182.3 ± 6.6 cm, 99.1 ± 18.4 kg) were measured for selected anthropometric variables and 1RM bench press at the conclusion of a heavy resistance training program. Triceps, subscapular, and abdominal skinfolds were measured in triplicate by three investigators and used to estimate %fat. Arm circumference was measured around a flexed biceps muscle and was corrected for triceps skinfold to estimate muscle cross-sectional area (CSA). Chest circumference was measured at mid-expiration. Significant differences among the testers were evident in six of the nine anthropometric variables, with the least experienced tester being significantly different from the other testers on seven variables, although average differences among investigators ranged from 1-2% for circumferences to 4-9% for skinfolds. The two more experienced testers were significantly different on only one variable. Overall agreement among testers was high (ICC\u3e0.895) for each variable, with low coefficients of variation (CV\u3c10.7%). Predicted 1RMs for testers (126.9 ± 20.6, 123.4 ± 22.0, and 132.1 ± 28.4 kg, respectively) were not significantly different from actual 1RM (129.2 ± 20.6 kg). Individuals with varying levels of experience appear to have an acceptable level of ability to estimate 1RM bench press using a non-performance anthropometric equation. Minimal experience in anthropometry may not impede strength and conditioning specialists from accurately estimating 1RM bench press
Concordance Among Bioelectrical Impedance Analysis Measures Of Percent Body Fat In Athletic Young Adults
International Journal of Exercise Science 12(4): 324-331, 2019. The purpose of this investigation was to determine the agreement among three bioelectrical impedance analysis devices (BIA) in athletic young adults. Fifty-one participants (26 men and 25 women) were assessed for percent body fat (PBF) using an arm-to-arm bipolar single-frequency device (ABIA), a leg-to-leg single-frequency device (LBIA), and an octopolar multi-frequency BIA device (MFBIA). PBF was measured with the three devices in a randomized, counterbalanced order. Repeated measures ANOVA revealed significant (p \u3c 0.001) differences in PBF estimates among all devices (ABIA = 19.1 ± 7.2%, LBIA = 21.6 ±7.5%, and MFBIA = 22.9 ± 8.8%). Pearson’s Correlations revealed a strong relationship between ABIA and MFBIA in both men (r = 0.948) and women (r = 0.947) and a moderately-strong relationship between LBIA and MFBIA (r = 0.870 and 0.679, respectively). Lin’s concordance coefficient revealed moderately-strong concordance between ABIA and MFBIA in men (ρc= 0.800) and women (ρc= 0.681) and between LBIA and MFBIA (ρc = 0.846 and ρc= 0.651, respectively). These data indicate a strong agreement among all three devices, suggesting that any of them could be used to track changes in PBF over time. However, the significant differences in PBF values among devices imply that best practice for monitoring body composition should be to use one device consistently over time for a reliable assessment
Validity of Arm-to-Arm BIA Devices Compared to DXA for Estimating %fat in College Men and Women
International Journal of Exercise Science 10(7): 977-988, 2017. Bioelectric impedance analysis (BIA) devices are commonly used to estimate percent body fat (%fat), although validation of their accuracy varies widely. The purpose of this study was to assess the validity of four commonly used BIA devices compared to dual-energy X-ray absorptiometry (DXA). College-aged men (n = 29, age = 19.7 ± 1.2 y, weight = 76.9 ± 12.5 kg) and women (n = 31, age = 20.5 ± 0.8 y, weight = 61.5 ± 9.2 kg) were evaluated for %fat using four single-frequency (50 mHz) BIA devices and DXA. A gender x device repeated measures ANOVA indicated some less expensive BIA devices produced %fat values that were not significantly different from DXA. A thumb-to-thumb BIA device produced the closest values in men (21.9 ± 6.6%) and women (32.1 ± 5.3%) compared to DXA (20.6 ± 6.1% and 30.3 ± 5.4%, respectively). The two more expensive BIA devices significantly underestimated in men (14.7 ± 5.8% and 17.0 ± 5.6%) and women (23.3 ± 4.2% and 23.3 ± 4.2%) compared to DXA. Interclass correlation coefficients with DXA were higher for the more expensive devices in men (ICC = 0.899 and 0.958) than the less expensive devices (ICC = 0.681 and 0.730). In women, all BIA devices showed moderate correlations with DXA (ICC = 0.537 to 0.658). Despite the convenience of simple BIA devices, their use in estimating body composition in young men and women might be questionable due to large variations in the differences between DXA and each device in this stud
Momentum, Rather Than Velocity, Is a More Effective Measure of Improvements in Division IA Football Player Performance
Speed, or the time to complete straight runs or agility drills, is commonly used to assess performance in collegiate American football players. However, it is common for players\u27 speeds to plateau by the second year of eligibility, whereas their body masses continue to increase. The purpose of this study was to track change in speed, body mass, and momentum (body mass · velocity), across Division 1 football players\u27 4-year careers (n = 512). Complete data were derived for the 40-yd sprint (n = 82), the proagility shuttle (n = 73), and the L drill (n = 73) from the same NCAA Division 1 team over a 15-year period. Significant changes were seen for velocity between year 1 and the next 3 playing years (p \u3c 0.05), with no differences between years 2 and 4, whereas body mass increased significantly across all playing years (p \u3c 0.05). Further momentum increased across all years for all tests (p \u3c 0.0001). These results indicate the importance of including changes in body mass when evaluating performances during sprints and change of direction drills. Our results also suggest that using sprint or agility drill times to evaluate playing potential across football players\u27 collegiate careers may be ineffective and can provide players with a false and disheartening picture of their improvements across their careers. Momentum, which incorporates training-induced increases in both speed and body mass, would be a more relevant and supportive measure of players\u27 improvements. In addition, the simple computation of this variable, using existing speed and body mass data, may be an important addition to the National Football League combine as a measure of playing potential in the professional game
Similar Effects of 24 Weeks of Resistance Training Performed with Different Frequencies on Muscle Strength, Muscle Mass, and Muscle Quality in Older Women
International Journal of Exercise Science 12(6): 623-635, 2019. The purpose of this study was to analyze the effects of 24 weeks of resistance training (RT) performed 2 vs. 3 times per week on muscle strength, muscle mass, and muscle quality in older women. Thirty-nine older women (≥ 60 years old) were randomly assigned to two groups according to RT frequency (G2x = two sessions per week, n=19; and G3x = three sessions per week, n=20) and were submitted to 24 weeks of whole-body RT, divided into two stages of 12 weeks. In the first stage, participants performed 1 set of 10 to 15 repetitions in each of eight exercise, whereas in the second stage, they performed 2 sets of 10 to 15 repetitions. Muscle strength was assessed by one repetition maximum (1RM) tests in chest press, knee extension, and biceps preacher curl, while the lean soft tissue was estimated by DXA. The muscle quality index was determined by the ratio between strength and lean soft tissue. There were observed similar increases between groups for muscle strength (G2x=19.5%; G3x=22.2%), lean soft tissue (G2x=3.0%; G3x=1.6%), and muscle quality index (G2x=16.0%; G3x=21.1%). These results indicate that RT-induced muscular adaptation occurs regardless of training twice or thrice a week in older women. Instructors, coaches and practitioners can choose their training frequency preference, since both frequencies provided similar adaptations
Starting the Resistance-Training Session with Lower-Body Exercises Provides Lower Session Perceived Exertion without Altering the Training Volume in Older Women
International Journal of Exercise Science 12(4): 1187-1197, 2019.The aim of this study was to compare the acute effects of four resistance-training (RT) exercise orders on rate of perceived exertion (RPE) and RT variables with exercise load properly adjusted according to its position within the sequence in older women. That is, the load was adjusted so that it was possible that the sets were performed within the repetition-zone established. Fifteen trained older women (67.4 ± 5.3 years) participated in a crossover-design, combining single-joint (SJ) and multi-joint (MJ) exercises for upper- (UB) and lower-body (LB) in the following exercise orders: SEQA = UBMJ-UBSJ-LBMJ-LBMJ; SEQB = UBSJ-UBMJ-LBSJ-LBMJ; SEQC = LBMJ-LBSJ-UBMJ-UBSJ; SEQD = LBSJ-LBMJ-UBSJ-UBMJ. Each session was comprised of eight exercises with 3 sets of 8-12 repetitions. RPE was analyzed by a sequence (4) x sets (3) two-way ANOVA. Repetitions, time under tension, load, volume-load, and the average RPE of the session were analyzed by one-way ANOVA comparing the four sequences. No significant difference was identified between conditions for total repetitions, time under tension, training load, and volume-load. Lower average RPE of the session was obtained when LB exercises were performed earlier (SEQA: 7.2 ± 1.2, SEQB: 7.1 ± 1.0, SEQC: 6.7 ± 0.9, SEQD: 6.3 ± 1.1). We conclude that when lower body exercises are performed first in a training session, a lower RPE is noted throughout all the session
‘At risk’ waist-to-height ratio cut-off points recently adopted by NICE and US Department of Defense will unfairly penalize shorter adults. What is the solution?
Objectives
To a) demonstrate that adopting ‘at risk’ waist-to-height ratio (WHTR) cut-off points, recently approved by National Institute for Health and Care Excellence (NICE) and the United States Department of Defense (USDoD), will unfairly penalize shorter individuals and will be too lenient for taller individuals, b) to confirm that waist circumference (WC) of a sample of US service personnel, scales to approximately height0.5, supporting the notion that WC, to be independent of height (HT), should be normalized using WC.HT−0.5 (WHT•5R), and c) to identify the WHT•5R cut-off points that will reduce or eliminate this unwanted bias.
Subjects/methods
We employed a three independent cross-sectional sample design. All n = 58,742 participants underwent anthropometric assessment of body mass, stature and waist circumference.
Results
The allometric power-law model WC=a.HT^b for US service personnel identified the height exponent to be b= 0.418 (95 % CI 0.251–0.585), confirming that the simple body-shape index for WC to be independent of HT, should be WC.HT−0.5. Chi-square tests of independence and for linear trend confirmed that by adopting WHTR cut-off point, shorter individuals (both service personnel and non-service participants) will be over penalized (classified as being ‘at risk’). New WC independent-of-height ratio cut-off points were found to resolve this problem.
Conclusions
Adopting WHTR cut-off thresholds (either 0.5 or 0.55) will lead to shorter adults being unfairly classified as being ‘at risk’ in terms of their central adiposity and general health status. Adopting new WHT•5R cut-off point thresholds were found to greatly reduce or eliminate this bias
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The Clinical Outcome Study for dysferlinopathy: An international multicenter study
Objective: To describe the baseline clinical and functional characteristics of an international cohort of 193 patients with dysferlinopathy.
Methods: The Clinical Outcome Study for dysferlinopathy (COS) is an international multicenter study of this disease, evaluating patients with genetically confirmed dysferlinopathy over 3 years. We present a cross-sectional analysis of 193 patients derived from their baseline clinical and functional assessments.
Results: There is a high degree of variability in disease onset, pattern of weakness, and rate of progression. No factor, such as mutation class, protein expression, or age at onset, accounted for this variability. Among patients with clinical diagnoses of Miyoshi myopathy or limb-girdle muscular dystrophy, clinical presentation and examination was not strikingly different. Respiratory impairment and cardiac dysfunction were observed in a minority of patients. A substantial delay in diagnosis was previously common but has been steadily reducing, suggesting increasing awareness of dysferlinopathies.
Conclusions: These findings highlight crucial issues to be addressed for both optimizing clinical care and planning therapeutic trials in dysferlinopathy. This ongoing longitudinal study will provide an opportunity to further understand patterns and variability in disease progression and form the basis for trial design
Assessing Dysferlinopathy Patients Over Three Years With a New Motor Scale
The Jain COS Consortium.[Objective] Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD.[Methods] We collected a longitudinal series of functional assessments from 187 patients with dysferlinopathy over 3 years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and nonambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories.[Results] The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3 to 8 years post symptom onset at baseline.[Interpretation] The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinical practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short-term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy. ANN NEUROL 2021;89:967–978The estimated US $4 million needed to fund this study was provided by the Jain Foundation. (www.jain-foundation.org) The Jain COS consortium would like to thank the study participants and their families for their invaluable contribution. The John Walton Centre Muscular Dystrophy Research Centre is part of the MRC Centre for Neuromuscular Diseases (Grant number MR/K000608/1).Peer reviewe
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