Telomeres act as a mitotic clock and telomere-related senescence has been linked to age-related physiological decline. There is increasing evidence lifestyle factors can influence telomere length (TL). The purpose of this study was to determine the effect of competitive triathlon training on TL. Seven competitive male triathletes and seven recreationally active males participated in the study. Relative TL was measured using quantitative polymerase chain reaction. Physiological parameters key to athletic performance such as maximal oxygen intake, lactate threshold, and running economy were also measured. Triathletes had longer telomeres than the recreationally active (1.257 ± 0.028 vs. 1.002 ± 0.014; p < .0001). Positive association was found between TL and maximal oxygen intake, lactate threshold, and running economy (R 2 = .677, .683, and .696, respectively). This study indicates that competitive triathlon training buffers against age-related telomere shortening, and there is a correlation between exercise behaviors, higher maximal oxygen intake, and TL.
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Marcus Colon, Andrew Hodgson, Eimear Donlon and James E.J. Murphy
Patrick Ippersiel, Richard Preuss and Shawn M. Robbins
Continuous relative phase (CRP) analysis using the Hilbert transform is prone to end effects. The purpose was to investigate the impact of padding techniques (reflection, spline extrapolation, extraneous data, and unpadded) on end effects following Hilbert-transformed CRP calculations, using sinusoidal, nonsinusoidal, and kinematic data from a repeated sit-to-stand-to-sit task in adults with low back pain (n = 16, mean age = 30 y). CRP angles were determined using a Hilbert transform of sinusoidal and nonsinusoidal signals with set phase shifts, and for the left thigh/sacrum segments. Root mean square difference and true error compared test signals with a gold standard, for the start, end, and full periods, for all data. Mean difference and 95% bootstrapped confidence intervals were calculated to compare padding techniques using kinematic data. The unpadded approach showed near-negligible error using sinusoidal data across all periods. No approach was clearly superior for nonsinusoidal data. Spline extrapolation showed significantly less root mean square difference (all periods) when compared with double reflection (full period: mean difference = 2.11; 95% confidence interval, 1.41 to 2.79) and unpadded approaches (full period: mean difference = −15.8; 95% confidence interval, −18.9 to −12.8). Padding sinusoidal data when performing CRP analyses are unnecessary. When extraneous data have not been collected, our findings recommend padding using a spline to minimize data distortion following Hilbert-transformed CRP analyses.
Judith Jiménez-Díaz, Karla Chaves-Castro and Walter Salazar
Background: To use the meta-analytic approach to assess the effectiveness of different types of movement programs on motor competence (MC) in participants of all ages. Methods: Studies were retrieved by searching 13 databases and included when criteria were met. Studies were selected, and data were extracted by 2 authors. Random effects models using the standardized mean difference effect size (ES) were used to pool results. Risk of bias, heterogeneity, and inconsistency were examined. Results: Thirty-six studies met the inclusion criteria. A total of 374 ESs were calculated and partitioned into 4 groups (motor intervention, free play, physical education classes, and control group). Statistically significant improvements in MC were observed for the motor intervention (ES = 1.50; 95% confidence interval [CI], 1.18 to 1.82; n = 36), as well as for free play (ES = 0.33; 95% CI, 0.09 to 0.57; n = 5), physical education classes (ES = 0.52; 95% CI, 0.08 to 0.97; n = 15), and smaller statistically significant differences in MC were observed for the control groups (ES = 0.16; 95% CI, 0.01 to 0.31; n = 6). Conclusions: All 4 groups analyzed improved MC in children, adolescents, and young adults. However, motor interventions were superior to all other groups for improving MC.
Gislaine S. Kogure, Cristiana L. Miranda-Furtado, Daiana C.C. Pedroso, Victor B. Ribeiro, Matheus C. Eiras, Rafael C. Silva, Lisandra C. Caetano, Rui A. Ferriani, Rodrigo T. Calado and Rosana M. dos Reis
Background: Physical activity is prescribed as a component of primary management for polycystic ovary syndrome (PCOS). This nonrandomized, therapeutic, open, single-arm study investigated the effects of progressive resistance training (PRT) on obesity indices in women with PCOS, and the relationship between obesity indices and telomere content. Methods: A total of 45 women with PCOS and 52 with non-PCOS (controls), aged 18 to 37 years, with body mass indexes of 18 to 39.9 kg/m2, performed three 1-hour sessions of PRT per week, for 16 weeks. Before and after PRT, measures included anthropometric indices and regions of interest of fat mass distribution, quantified by dual-energy X-ray absorptiometry, metabolic and hormonal parameters, and telomere content. The general linear mixed models were used to determine the effects of PRT. Results: PRT did reduce the waist-to-height ratio, waist circumference, and the index of conicity among PCOS (P < .01). However, PRT did not influence regions of interest, body mass index, and WHR. After PRT, the telomere content was associated with regions of interest and anthropometric indices in whole group independent of PCOS (P < .05). Conclusion: Resistance exercise improves obesity indices in PCOS, independent of changes in body weight, and the relationship between telomeres and obesity parameters in PCOS remain to be fully clarified.
Hellen C.G. Nabuco, Crisieli M. Tomeleri, Rodrigo R. Fernandes, Paulo Sugihara Junior, Edilaine F. Cavalcante, Danielle Venturini, Décio S. Barbosa, Analiza M. Silva, Luís B. Sardinha and Edilson S. Cyrino
The objective of this study was to investigate the effects of protein intake beyond habitual intakes associated with resistance training on metabolic syndrome (MetS)-related parameters, isokinetic strength, and body composition in health older women. A total of 30 older women (68.8 ± 4.3 years) participated in this investigation and were assigned to receive 35 g of whey protein or placebo combined with resistance training, over 12-weeks, three times per week. Blood samples, blood pressure, dietary intake, strength, and body composition were assessed before and after the intervention period. Two-way analysis of variance for repeated measures was applied for comparisons. Both groups improved the skeletal muscle mass, muscular strength, waist circumference, triglycerides, high-density lipoprotein, glucose, resistance, reactance, and MetS Z-score risk. However, the improvements in skeletal muscle mass, waist circumference, and MetS Z-score risk were significantly greater in protein group when compared with control group. Moreover, protein group significantly decreased %body fat when compared with control group. Higher protein intake combined with resistance training promoted greater improvements in skeletal muscle mass, %body fat, waist circumference, and MetS Z-score risk in older women.
Martyn Rothwell, Joseph Stone and Keith Davids
Social, cultural, and historical constraints can influence attitudes towards learning, developing, and performing in sport. A recent conceptualization of these environmental constraints in athlete development pathways is a form of life, which describes the values, beliefs, traditions, customs, and behaviors that contribute to an athlete’s development. Although a form of life can have a powerful influence on athlete development, research exploring this relationship is limited. In this article we explore the form of life in British rugby league football player development contexts to clarify how social, cultural, and historical constraints influence the development of rugby league players in the United Kingdom. Twenty-four coaches were interviewed through individual semi-structured interviews to collect the data. Findings show how forms of life in rugby league player development pathways are established and maintained by the complex interactions between the microsystem, mesosystem, exosystem, and macrosystem that shape and guide the development of players. We recommend that player development pathways in sport underpin practice with a theoretical framework of the learning process to protect athletes from social, cultural, and historical constraints that are not conducive to their development.
Nick Dobbin, Jamie Highton, Samantha Louise Moss and Craig Twist
Purpose: To investigate the factors affecting the anthropometric and physical characteristics of elite academy rugby league players. Methods: One hundred ninety-seven elite academy rugby league players (age = 17.3 [1.0] y) from 5 Super League clubs completed measures of anthropometric and physical characteristics during a competitive season. The interaction between and influence of contextual factors on characteristics was assessed using linear mixed modeling. Results: All physical characteristics improved during preseason and continued to improve until midseason, whereafter 10-m sprint (η 2 = .20 cf .25), countermovement jump (CMJ) (η 2 = .28 cf .30), and prone Yo-Yo Intermittent Recovery (Yo-Yo IR) test (η 2 = .22 cf .54) performance declined. Second (η 2 = .17) and third (η 2 = .16) -year players were heavier than first-years, whereas third-years had slower 10-m sprint times (η 2 = .22). Large positional variability was observed for body mass, 20-m sprint time, medicine-ball throw, CMJ, and prone Yo-Yo IR1. Compared with bottom-ranked teams, top-ranked teams demonstrated superior 20-m (η 2 = −.22) and prone Yo-Yo IR1 (η 2 = .26) performance, whereas middle-ranked teams reported higher CMJ height (η 2 = .26) and prone Yo-Yo IR1 distance (η 2 = .20) but slower 20-m sprint times (η 2 = .20). Conclusion: These findings offer practitioners who design training programs for academy rugby league players insight into the relationships between anthropometric and physical characteristics and how they are influenced by playing year, league ranking, position, and season phase.
Cesar Gallo-Salazar, Juan Del Coso, David Sanz-Rivas and Jaime Fernandez-Fernandez
Purpose: To determine whether the game activity and physiological responses of young tennis players differed depending on the session of play (eg, morning [MOR] vs afternoon [AFT]) and the final match outcome (eg, winners vs losers) during a simulated competition with 2 matches on the same day. Methods: A total of 12 well-trained male tennis players (age 14.5 [0.8] y) took part in a simulated competition of two 3-set matches separated by 3 h. All the matches were video recorded, and the participants were monitored using 10-Hz global positioning system units including a heart-rate monitor. Effect-size (ES) statistics were used to investigate the magnitudes of the differences. Results: During the AFT matches, in absolute terms, players covered longer total distance (ES = moderate) and ran more distance between 0 and ≤4 m·s−1 (ES = small to large) than in MOR matches. Total duration was also longer (ES = large) in the AFT, where the rest time between rallies was also longer (ES = very large). Heart rate was similar during AFT and MOR matches, but higher rates of perceived exertion (ES = moderate) were reported in the AFT. Only peak running velocity was observed to be likely higher for losers than for winners (ES = small). Conclusions: Game activity and physiological responses of young tennis players differ when 2 consecutive matches are played on the same day. These data might help elucidate the need for specific precompetition training loads and/or between-matches/sessions recovery strategies when facing overloaded competitions.
Ralph Beneke and Renate M. Leithäuser
David R. Howell, Thomas A. Buckley, Brant Berkstresser, Francis Wang and William P. Meehan III
The purpose of this study was to identify the rate of abnormal single-task and dual-task gait performance following concussion compared to uninjured controls using previously established normative reference values. The authors examined athletes with a concussion (n = 54; mean age = 20.3 [1.1] y, 46% female, tested 2.9 [1.5] d postinjury), and healthy controls were tested during their preseason baseline examination (n = 60; mean age = 18.9 [0.7] y, 37% female). Participants completed an instrumented single-/dual-task gait evaluation. Outcome variables included average walking speed, cadence, and step length. A significantly greater number of those with concussion walked with abnormal dual-task gait speed compared with the control group (56% vs 30%, P = .01). After adjusting for potential confounding variables (age, concussion history, symptom severity, and sleep), concussion was associated with lower dual-task gait speed (β = −0.150; 95% confidence interval [CI] = −0.252 to −0.047), cadence (β = −8.179; 95% CI = −14.49 to −1.871), and stride length (β = −0.109; 95% CI = −0.204 to −0.014). Although group analyses indicated that those with a concussion performed worse on single-task and dual-task gait compared with controls, a higher rate of abnormal gait was detected for the concussion group compared with the control group for dual-task gait speed only. Dual-task gait speed, therefore, may be considered as a measure to compare against normative values to detect postconcussion impairments.