scholarly journals Longitudinal tracking of body composition, lower limb force-time characteristics and swimming start performance in high performance swimmers

2021 ◽  
pp. 174795412110214
Author(s):  
Shiqi Thng ◽  
Simon Pearson ◽  
Evelyne Rathbone ◽  
Justin WL Keogh
Keyword(s):  
Body Composition ◽  
Lean Mass ◽  
High Performance ◽  
Body Force ◽  
Lower Body ◽  
Squat Jump ◽  
Competitive Season ◽  
Positive Correlations ◽  
Force Time ◽  
Body Lean Mass

This study aimed to (1) track changes in body composition, lower body force-time characteristics, and swim start performance over a competitive season, and (2) investigate the intra-individual associations between changes in body composition and lower body force-time characteristics to swim start performance in five high performance swimmers (three males, two females). Over a ∼12-month period, body composition, lower body force-time characteristics and swim start performance were assessed at three time points via DXA scan, squat jump and swim start performance test (start times to 5 and 15 m and several kinematic and kinetic outputs). Throughout a competitive season of concurrent swimming and dry-land resistance training, improvements in lower body lean mass and squat jump force-time characteristics were observed. However, changes in start times varied between athletes. Total body and lower body lean mass both displayed large negative correlations with the time spent in the entry and propulsive underwater phases ( r = –0.57 to –0.66), along with a large positive correlations with glide time ( r = 0.56–0.53). Additionally, lower body lean mass exhibited large to very large positive correlations with the flight phase ( r = 0.70–0.73). Overall, these findings provide some insight into the potential magnitude of change in body composition, lower body force-time characteristics and swim start performance in high performance swimmers within a season. The large to very large correlations between increased lower body lean mass and SJ force-time metrics to improvements in aspects of start performance may provide useful information to coaches and sports scientists.

Body Composition and Muscle Strength as Determinants of Racial Difference in Bone Mineral Density

2001 ◽  
Vol 9 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Youn Soo Jung ◽  
Steven A. Hawkins ◽  
Robert A. Wiswell
Keyword(s):  
Bone Mineral Density ◽  
Body Composition ◽  
Muscle Strength ◽  
Racial Differences ◽  
Body Mass ◽  
Bone Mineral ◽  
Lean Mass ◽  
White Women ◽  
Lower Body ◽  
Mineral Density

The purpose of this study was to determine the contribution of body composition and muscle strength to racial differences in bone mineral density (BMD) in chronically active older adults. Participants were 49 men and 56 women grouped according to self-selected race (Black, Asian, or White). BMD, body composition, and knee strength were measured. Asian men had significantly lower body mass, strength, and BMD than White and Black men did (p < .05). Asian and White women had significantly lower body mass and BMD than Black women did (p < .05), with few strength differences between groups. When lean mass was controlled by ANCOVA. racial differences in BMD disappeared for all bone sites in both sexes. Controlling for body mass eliminated most racial differences in BMD. Controlling for strength did not alter racial differences in BMD for either sex. These results suggest that racial differences in BMD might in part result from differences in lean mass.

scholarly journals The prediction of swim start performance based on squat jump force-time characteristics

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9208
Author(s):  
Shiqi Thng ◽  
Simon Pearson ◽  
Evelyne Rathbone ◽  
Justin W.L. Keogh
Keyword(s):  
Body Mass ◽  
National Level ◽  
Multiple Regression Model ◽  
Lower Body ◽  
Strength Index ◽  
Mean Power ◽  
Front Crawl ◽  
Jump Performance ◽  
Squat Jump ◽  
Force Time

Background Depending on the stroke and distances of the events, swim starts have been estimated to account for 0.8% to 26.1% of the overall race time, with the latter representing the percentage in a 50 m sprint front crawl event (Cossor & Mason, 2001). However, it is still somewhat unclear what are the key physiological characteristics underpinning swim start performance. The primary aim of this study was to develop a multiple regression model to determine key lower body force-time predictors using the squat jump for swim start performance as assessed by time to 5 m and 15 m in national and international level swimmers. A secondary aim was to determine if any differences exist between males and females in jump performance predictors for swim start performance. Methods A total of 38 males (age 21 ±  3.1 years, height 1.83 ±  0.08 m, body mass 76.7 ±  10.2 kg) and 34 females (age 20.1 ±  3.2 years, height 1.73 ±  0.06 m, body mass 64.8 ±  8.4 kg) who had competed at either an elite (n = 31) or national level (n = 41) participated in this study. All tests were performed on the same day, with participants performing three bodyweight squat jumps on a force platform, followed by three swim starts using their main swimming stroke. Swim start performance was quantified via time to 5 m and 15 m using an instrumented starting block. Results Stepwise multiple linear regression with quadratic fitting identified concentric impulse and concentric impulse2 as statistically significant predictors for time to 5 m (R2 = 0.659) in males. With time to 15 m, concentric impulse, age and concentric impulse2 were statistically significant predictors for males (R2 = 0.807). A minimum concentric impulse of 200–230 N.s appears required for faster times to 5 m and 15 m, with any additional impulse production not being associated with a reduction in swim start times for most male swimmers. Concentric impulse, Reactive strength index modified and concentric mean power were identified as statistically significant predictors for female swimmers to time to 5 m (R2 = 0.689). Variables that were statistically significant predictors of time to 15 m in females were concentric impulse, body mass, concentric rate of power development and Reactive strength index modified (R2 = 0.841). Discussion The results of this study highlight the importance of lower body power and strength for swim start performance, although being able to produce greater than 200 or 230 N.s concentric impulse in squat jump did not necessarily increase swim start performance over 5 m and 15 m, respectively. Swimmers who can already generate greater levels of concentric impulse may benefit more from improving their rate of force development and/or technical aspects of the swim start performance. The sex-related differences in key force-time predictors suggest that male and female swimmers may require individualised strength and conditioning programs and regular monitoring of performance.

scholarly journals Three-Compartment Body Composition in Academy and Senior Rugby League Players

2016 ◽  
Vol 11 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Kevin Till ◽  
Ben Jones ◽  
John O’Hara ◽  
Matthew Barlow ◽  
Amy Brightmore ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Mass ◽  
Fat Mass ◽  
Lean Mass ◽  
Rugby League ◽  
Effect Sizes ◽  
Body Fat Percentage ◽  
Lower Body ◽  
Fat Percentage ◽  
Regional Body Composition

Purpose:To compare the body size and 3-compartment body composition between academy and senior professional rugby league players using dual-energy X-ray absorptiometry (DXA).Methods:Academy (age 18.1 ± 1.1 y, n = 34) and senior (age 26.2 ± 4.6 y, n = 63) rugby league players received 1 total-body DXA scan. Height, body mass, and body-fat percentage alongside total and regional fat mass, lean mass, and bone mineral content (BMC) were compared. Independent t tests with Cohen d effect sizes and multivariate analysis of covariance (MANCOVA), controlling for height and body mass, with partial eta-squared (η2) effect sizes, were used to compare total and regional body composition.Results:Senior players were taller (183.2 ± 5.8 vs 179.2 ± 5.7 cm, P = .001, d = 0.70) and heavier (96.5 ± 9.3 vs 86.5 ± 9.0 kg, P < .001, d = 1.09) with lower body-fat percentage (16.3 ± 3.7 vs 18.0 ± 3.7%, P = .032, d = 0.46) than academy players. MANCOVA identified significant overall main effects for total and regional body composition between academy and senior players. Senior players had lower total fat mass (P < .001, η 2 = 0.15), greater total lean mass (P < .001, η 2 = 0.14), and greater total BMC (P = .001, η 2 = 0.12) than academy players. For regional sites, academy players had significantly greater fat mass at the legs (P < .001, η 2 = 0.29) than senior players.Conclusions:The lower age, height, body mass, and BMC of academy players suggest that these players are still developing musculoskeletal characteristics. Gradual increases in lean mass and BMC while controlling fat mass is an important consideration for practitioners working with academy rugby league players, especially in the lower body.

scholarly journals Intake of Animal Protein Blend Plus Carbohydrate Improves Body Composition With no Impact on Performance in Endurance Athletes

2019 ◽  
Vol 29 (5) ◽  
pp. 474-480
Author(s):  
Fernando Naclerio ◽  
Eneko Larumbe-Zabala ◽  
Mar Larrosa ◽  
Aitor Centeno ◽  
Jonathan Esteve-Lanao ◽  
...  
Keyword(s):  
Body Composition ◽  
Lean Mass ◽  
Orange Juice ◽  
Animal Protein ◽  
Endurance Athletes ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Maximal Aerobic Speed ◽  
The Impact ◽  
Body Lean Mass

The impact of animal protein blend supplements in endurance athletes is scarcely researched. The authors investigated the effect of ingesting an admixture providing orange juice and protein (PRO) from beef and whey versus carbohydrate alone on body composition and performance over a 10-week training period in male endurance athletes. Participants were randomly assigned to a protein (CHO + PRO, n = 15) or a nonprotein isoenergetic carbohydrate (CHO, n = 15) group. Twenty grams of supplement mixed with orange juice was ingested postworkout or before breakfast on nontraining days. Measurements were performed pre- and postintervention on body composition (by dual-energy X-ray absorptiometry), peak oxygen consumption (), and maximal aerobic speed. Twenty-five participants (CHO + PRO, n = 12; CHO, n = 13) completed the study. Only the CHO + PRO group significantly (p < .05) reduced whole-body fat (mean ± SD) (−1.02 ± 0.6 kg), total trunk fat (−0.81 ± 0.9 kg), and increased total lower body lean mass (+0.52 ± 0.7 kg), showing close to statistically significant increases of whole-body lean mass (+0.57 ± 0.8 kg, p = .055). Both groups reduced (p < .05) visceral fat (CHO + PRO, −0.03 ± 0.1 kg; CHO, −0.03 ± 0.5 kg) and improved the speed at maximal aerobic speed (CHO + PRO, +0.56 ± 0.5 km/hr; CHO, +0.35 ± 0.5 km/hr). Although consuming animal protein blend mixed with orange juice over 10 weeks helped to reduce fat mass and to increase lean mass, no additional performance benefits in endurance runners were observed.

scholarly journals Conjugated linoleic acid (CLA) and obesity

2007 ◽  
Vol 10 (10A) ◽  
pp. 1181-1186 ◽  
Author(s):  
Manuela-Belén Silveira ◽  
Raffaele Carraro ◽  
Susana Monereo ◽  
Javier Tébar
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Body Fat ◽  
Lean Mass ◽  
Weight Regain ◽  
Cla Isomers ◽  
Harmful Effects ◽  
Body Lean Mass

AbstractBackgroundThe term conjugated linoleic acid (CLA) refers to several positional and geometric conjugated dienoic isomers of linoleic acid (LA), of which the trans-10,cis-12 isomer has been reported to reduce adiposity and increase lean mass in mice and other animals when included at ≤1% of the diet. However, most dietary CLA in humans is obtained from dairy products, accounting for the cis-9,trans-11 CLA isomer, also known as rumenic acid, for more than 90% of the total CLA intake. Commercial CLA preparations industrially produced, containing trans-10,cis-12 and cis-9,trans-11 CLA isomers in diverse proportions, are attracting consumers’ interest because of the purported body fat-lowering effects of CLA, coupled to the perception of a ‘natural’ compound devoid of harmful effects. Nevertheless, despite numerous studies on CLA effects on body composition for nearly a decade, the mechanisms by which CLA isomers elicit their effects remain largely unknown. The purpose of this paper is to provide an updated review of the studies performed on animals and humans, as well as to describe the potential mechanisms involved in CLA effects on body weight and composition and metabolism.MethodLiterature review.ResultsExperiments in humans have not been able to show a significant effect on body weight, body composition or weight regain related to either of the CLA isomers. In fact, some studies suggest a tendency towards a decrease in body fat mass and an increase in body lean mass, while some others raise concern about the possibility of deleterious effects of trans-10,cis-12 CLA on lipid profile, glucose metabolism and insulin sensitivity.ConclusionsEvidence regarding effectiveness of CLA in humans is not concluding.

scholarly journals WOMEN’S FEMORAL MASS CONTENT CORRELATES TO MUSCLE STRENGTH INDEPENDENTLY OF LEAN BODY MASS

2019 ◽  
Vol 25 (6) ◽  
pp. 485-489
Author(s):  
Luciana Duarte Pimenta ◽  
Danilo Alexandre Massini ◽  
Daniel Dos Santos ◽  
Leandro Oliveira Da Cruz Siqueira ◽  
Andrei Sancassani ◽  
...  
Keyword(s):  
Body Composition ◽  
Muscle Strength ◽  
Lean Body Mass ◽  
Muscle Mass ◽  
Body Mass ◽  
Lean Mass ◽  
The Body ◽  
Whole Body ◽  
Regional Body Composition ◽  
Body Lean Mass

ABSTRACT Introduction There is limited consensus regarding the recommendation of the most effective form of exercise for bone integrity, despite the fact that weight training exercise promotes an increase in muscle mass and strength as recurrent responses. However, strength variations in women do not depend on muscle mass development as they do in men, but strength enhancement has shown the potential to alter bone mineral content (BMC) for both sexes. Objective This study analyzed the potential of muscle strength, as well as that of whole-body and regional body composition, to associate femoral BMC in young women. Methods Fifteen female college students (aged 24.9 ± 7.2 years) were assessed for regional and whole-body composition using dual-energy X-ray absorptiometry (DXA). Maximum muscle strength was assessed by the one-repetition maximum (1RM) test in the following exercises: bench press (BP), lat pulldown (LP), knee flexion (KF), knee extension (KE) and 45° leg press (45LP). Linear regression analyzed BMC relationships with regional composition and 1RM values. Dispersion and error measures (R 2 aj and SEE), were tested, defining p ≤0.05. Results Among body composition variables, only total lean body mass was associated with femoral BMC values (R 2 aj = 0.37, SEE = 21.3 g). Regarding strength values, 1RM presented determination potential on femoral BMC in the CE exercise (R 2 aj = 0.46, SEE = 21.3 g). Conclusions Muscle strength aptitude in exercises for femoral regions is relevant to the femoral mineralization status, having associative potential that is similar to and independent of whole-body lean mass. Therefore, training routines to increase muscle strength in the femoral region are recommended. In addition, increasing muscle strength in different parts of the body may augment bone remodeling stimulus, since it can effectively alter total whole-body lean mass. Level of Evidence II; Development of diagnostic criteria in consecutive patients (with universally applied reference ‘‘gold’’ standard).

scholarly journals Impact of Kinanthropometric Differences According to Non-Professional Sports Activity Practiced

2021 ◽  
Vol 11 (11) ◽  
pp. 5063
Author(s):  
Daniel J. Navas Harrison ◽  
Ana María Pérez Pico ◽  
Raquel Mayordomo
Keyword(s):  
Physical Activity ◽  
Body Composition ◽  
Professional Sports ◽  
Whole Body ◽  
Lower Body ◽  
Basketball Players ◽  
Sports Activity ◽  
Sedentary Population ◽  
Activity Performance ◽  
Amateur Athlete

Kinanthropometry allows us to analyze variations in physical dimensions and body composition. This study’s objective was to evaluate the kinanthropometric differences based on physical activity performance, depending on whether the lower body or the whole body is more or less potent and the differences with a sedentary population. We analyzed 131 individuals (74 men and 57 women), with an average age of 22.68 ± 2.98 years. We differentiated three populations: sedentary (n = 63), runners (n = 20), and basketball players (n = 48). Measurements and indices were obtained following the international protocol of the International Society for the Advancement of Kinanthropometry (ISAK). The results show differences between the populations regarding weight, height, wingspan, and certain perimeters, diameters, and morphotypes depending on the predominant training type and the sedentary population. These anthropometric measurements will allow the amateur athlete to compare between seasons or other moments of training, pay attention to their evolution, and assess the possibility of changes in training.

scholarly journals Role of the Appendicular Skeletal Muscle Index for Predicting the Recurrence-Free Survival of Head and Neck Cancer

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 309
Author(s):  
Kun-Yun Yeh ◽  
Hang Huong Ling ◽  
Shu-Hang Ng ◽  
Cheng-Hsu Wang ◽  
Pei-Hung Chang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Composition ◽  
Head And Neck Cancer ◽  
Mass Loss ◽  
Lean Mass ◽  
Recurrence Free Survival ◽  
Skeletal Muscle Index ◽  
Free Survival ◽  
Prognostic Predictor ◽  
Appendicular Skeletal Muscle

Background: This study investigates whether the appendicular skeletal muscle index (ASMI) was an independent prognostic predictor for patients with locally advanced head and neck cancer (LAHNC) receiving concurrent chemoradiotherapy (CCRT) and whether there were any differences in lean mass loss in different body regions during CCRT. Methods: In this prospective study, we analyzed the clinicopathological variables and the total body composition data before and after treatment. The factors associated with the 2-year recurrence-free survival rate (RFSR) were analyzed via logistic regression analysis. Results: A total of 98 patients were eligible for analysis. The body weight, body mass index, and all parameters of body composition significantly decreased after CCRT. The pretreatment ASMI was the only independent prognostic factor for predicting the 2-year RFSR (hazard ratio, 0.235; 95% confidence interval, 0.062–0.885; p = 0.030). There was at least 5% reduction in total lean and fat mass (p < 0.001); however, the highest lean mass loss was observed in the arms (9.5%), followed by the legs (7.2%), hips (7.1%), waist (4.7%), and trunk (3.6%). Conclusions: The pretreatment ASMI was the only independent prognostic predictor for the 2-year RFSR of LAHNC patients undergoing CCRT. Asynchronous loss of lean mass may be observed in different body parts after CCRT.

Body Mass and Body Composition Changes over 7 Years in a Male Professional Rugby Union Team

2021 ◽  
Author(s):  
Clíodhna McHugh ◽  
Karen Hind ◽  
Aoife O'Halloran ◽  
Daniel Davey ◽  
Gareth Farrell ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Mass ◽  
Body Fat ◽  
Lean Mass ◽  
Total Mass ◽  
Rugby Union ◽  
Body Fat Percentage ◽  
Fat Percentage ◽  
Dxa Scans ◽  
Composition Changes

AbstractThe purpose of this study was to investigate longitudinal body mass and body composition changes in one professional rugby union team (n=123), (i) according to position [forwards (n=58) versus backs (n=65)], analysis of players with 6 consecutive seasons of DXA scans (n=21) and, (iii) to examine differences by playing status [academy and international], over 7 years. Players [mean age: 26.8 y, body mass index: 28.9+kg.m2] received DXA scans at fourtime points within each year. A modest (but non-significant) increase in mean total mass (0.8 kg) for professional players was reflected by increased lean mass and reduced body fat mass. At all-time points, forwards had a significantly greater total mass, lean mass and body fat percentage compared to backs (p<0.05). Academy players demonstrated increased total and lean mass and decreased body fat percentage over the first 3 years of senior rugby, although this was not significant. Senior and academy international players had greater lean mass and lower body fat percentage (p<0.05) than non-international counterparts. Despite modest increases in total mass; reflected by increased lean mass and reduced fat mass, no significant changes in body mass or body composition, irrespective of playing position were apparent over 7 years.

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