Browse

You are looking at 41 - 50 of 28,557 items for :

Clear All
Restricted access

Danny Lum and Abdul Rashid Aziz

Force–time characteristics obtained during isometric strength tests are significantly correlated to various sporting movements. However, data on the relationship between isometric force–time characteristics and sprint kayaking performance are lacking in the literature. Purpose: The purpose of the study was, therefore, to investigate the relationship between sprint kayaking performance with ergometer performance and measures from 3 isometric strength tests: isometric squat, isometric bench press, and isometric prone bench pull. Methods: A total of 23 sprint kayaking athletes performed all 3 tests, at 90° and 120° knee angles for isometric squat and at elbow angles for isometric bench press and isometric prone bench pull, and a 200-m sprint on-water to attain the fastest time-to-completion (OWTT) possible and on a kayak ergometer to attain the highest mean power (LABTT) possible. Results: There was a significant inverse correlation between OWTT and LABTT (r = −.90, P < .001). The peak forces achieved from all isometric strength tests were significantly correlated with time-to-completion for OWTT and mean power for LABTT (r = −.44 to −.88, P < .05 and .47 to .80, P < .05, respectively). OWTT was significantly correlated with the peak rate of force development during all isometric tests except for the isometric squat at a 120° knee angle (r = −.47 to −.62, P < .05). LABTT was significantly correlated with peak rate of force development from the isometric bench press and isometric prone bench pull (r = .64–.86, P < .01). Conclusion: Based on the observed strong correlations, the mean power attained during LABTT is a good predictor of OWTT time-to-completion. Furthermore, upper- and lower-body maximum strength and peak rate of force development are equally important for on-water and ergometer sprint kayaking performance.

Restricted access

Jonathan I. Hochstetler, Anne C. Russ, Ryan Tierney and Jamie L. Mansell

Focused Clinical Question: In athletic training, what is the percentage of workplace bullying compared to the percentage in nursing? Clinical Bottom Line: There is evidence that workplace bullying is prevalent in the athletic training and nursing professions.

Restricted access

Alex S. Ribeiro, Ademar Avelar, Witalo Kassiano, João Pedro Nunes, Brad J. Schoenfeld, Andreo F. Aguiar, Michele C.C. Trindade, Analiza M. Silva, Luís B. Sardinha and Edilson S. Cyrino

The authors aimed to compare the effects of creatine (Cr) supplementation combined with resistance training on skeletal muscle mass (SMM), total body water, intracellular water (ICW), and extracellular water (ECW) in resistance-trained men as well as to determine whether the SMM/ICW ratio changes in response to the use of this ergogenic aid. Twenty-seven resistance-trained men received either Cr (n = 14) or placebo (n = 13) over 8 weeks. During the same period, subjects performed two split resistance training routines four times per week. SMM was estimated from appendicular lean soft tissue assessed by dual-energy X-ray absorptiometry. Total body water, ICW, and ECW were determined by spectral bioelectrical impedance. Both groups showed improvements (p < .05) in SMM, total body water, and ICW, with greater values observed for the Cr group compared with placebo. ECW increased similarly in both groups (p < .05). The SMM/ICW ratio did not change in either group (p > .05), whereas the SMM/ECW ratio decreased only in the Cr group (p < .05). A positive correlation was observed (p < .05) between SMM and ICW changes (r = .71). The authors’ results suggest that the increase in muscle mass induced by Cr combined with resistance training occurs without alteration of the ratio of ICW to SMM in resistance-trained men.

Restricted access

Marcelo Danillo Matos dos Santos, Felipe J. Aidar, Raphael Fabrício de Souza, Jymmys Lopes dos Santos, Andressa da Silva de Mello, Henrique P. Neiva, Daniel A. Marinho and Mário C. Marques

Purpose: To verify the effects of using different grip widths in bench press performance in Paralympic powerlifting athletes. Methods: Twelve experienced Paralympic powerlifting male athletes (25.40 [3.30] y, 70.30 [12.15] kg) participated in the study. Maximal dynamic strength and maximal isometric strength (MIS) were determined. Then, mean propulsive velocity (MPV) using 25%, 50%, and 100% of maximal dynamic strength load and time to achieve 30%, 50%, and 100% of MIS were assessed with 4 different grip widths, specifically the biacromial distance (BAD: 42.83 [12.84] cm), 1.3 BAD (55.68 [16.70] cm), 1.5 BAD (63.20 [18.96] cm), and 81 cm. Electromyographic analysis was performed during MIS assessment in the pectoralis major sternal portion, anterior deltoid, triceps brachii long head, and pectoralis major clavicular portion. Results: Large differences were found between MPV performed with different grip widths using 25% of maximal dynamic strength load (P = .02, ηp2=.26). The 1.5 BAD grip tended to show greater force generation and MPV. Moreover, the time needed to achieve 30%, 50%, and 100% of MIS differed between grip widths (P = .03, ηp2=.24), with the lowest values obtained in the 1.5 BAD. Despite the nonstatistical differences that were found, grip widths caused moderate effects on muscle myoelectric activation, showing greater values for pectoralis major clavicular portion and pectoralis major sternal portion, for the 1.3 BAD and 1.5 BAD, respectively. The 1.5 BAD the grip width tended to show greater MPV values and faster contractile responses. Conclusions: These results highlighted the importance of choosing the specific grip width for improvement of performance in Paralympic powerlifting athletes, by increasing velocity of movement and force production in a shorter time, with greater activation of primary muscles.

Restricted access

Keely Shaw, Jyotpal Singh, Luke Sirant, J. Patrick Neary and Philip D. Chilibeck

Dark chocolate (DC) is high in flavonoids and has been shown to increase nitric oxide in the blood. Increased nitric oxide has the potential to improve delivery of oxygen to muscle, especially in hypoxic conditions, such as altitude. Our aim was to assess the impact of DC supplementation on cycling performance at altitude. Twelve healthy, trained cyclists (n = 2 females, n = 10 males; age = 35 [12] years; height = 177 [7] cm; mass = 75.2 [11.0] kg; VO2max = 55 [6] ml·kg−1·min−1) were randomized to supplement with 60 g of DC or placebo twice per day for 14 days in a double-blind crossover study. After the 2 weeks of supplementation, the participants attended a laboratory session in which they consumed 120 g of DC or placebo and then cycled for 90 min at 50% peak power output, followed immediately by a 10-km time trial (TT) at simulated altitude (15% O2). The plasma concentration of blood glucose and lactate were measured before and at 15, 30, 60, and 90 min during the steady-state exercise and post TT, while muscular and prefrontal cortex oxygenation was measured continuously throughout exercise using near-infrared spectroscopy. DC resulted in a higher concentration of blood glucose (5.5 [0.5] vs. 5.3 [0.9] mmol/L) throughout the trial and lower blood lactate concentration following the TT (7.7 [1.92] vs. 10.0 [4.6] mmol/L) compared with the placebo. DC had no effect on the TT performance (19.04 [2.16] vs. 19.21 ± 1.96 min) or oxygenation status in either the prefrontal cortex or muscle. The authors conclude that, although it provided some metabolic benefit, DC is not effective as an ergogenic aid during TT cycling at simulated altitude.

Restricted access

Joshua McLeod, David Shilbury and Géraldine Zeimers

The purpose of this research was to examine the drivers and barriers of governance convergence in Indian sport. Governance convergence is defined as the adoption of four principles of good governance that are common in Western sport contexts—transparency, accountability, democracy, and social responsibility. To achieve the aim, a theoretical framework consisting of three interconnected levels—(a) the historically grown national institutional framework, (b) organizational field, and (c) organizational actors—was proposed, drawing primarily on institutional theory. A qualitative approach was used to empirically test the framework in the Indian sport context, where governance has been of key concern. The findings show that the framework is an effective tool for understanding the drivers and barriers of convergence with the defined principles of good governance. The development of this framework is important, given the link between the principles and positive organizational outcomes.

Restricted access

Jay A. Collison, Jason Moran, Inge Zijdewind and Florentina J. Hettinga

Purpose: To examine the differences in muscle fatigability after resistance exercise performed with fast tempo (FT) compared with slow tempo (ST). Methods: A total of 8 resistance-trained males completed FT and ST hexagonal-barbell deadlifts, consisting of 8 sets of 6 repetitions at 60% 3-repetition maximum, using a randomized crossover design. Each FT repetition was performed with maximal velocity, while each repetition during ST was performed with a 3-1-3 (eccentric/isometric/concentric) tempo (measured in seconds). Isometric maximal voluntary contraction, voluntary muscle activation, and evoked potentiated twitch torque of the knee extensors were determined using twitch interpolation before, during (set 4), and after exercise. Displacement–time data were measured during the protocols. Results: The mean bar velocity and total concentric work were higher for FT compared with ST (995 [166] W vs 233 [52] W; 0.87 [0.05] m/s vs 0.19 [0.05] m/s; 4.8 [0.8] kJ vs 3.7 [1.1] kJ). Maximal voluntary contraction torque, potentiated twitch, and voluntary muscle activation were significantly reduced after FT (−7.8% [9.2%]; −5.2% [9.2%], −8.7% [12.2%]) and ST (−11.2% [8.4%], −13.3% [8.1%], −1.8% [3.6%]). Conclusion: The decline in maximal voluntary force after both the FT and ST hexagonal-barbell deadlifts exercise was accompanied by a similar decline in contractile force and voluntary muscle activation.

Restricted access

Tyreal Yizhou Qian, Jerred Junqi Wang and James Jianhui Zhang

Shifting from a player-oriented approach, e-sports has increasingly positioned itself as emerging spectator entertainment. In the wake of the growing online viewer market, the industry has made tremendous efforts to innovate marketing strategies and build up a base of passionate fans across the globe. To augment this endeavor, the current study investigated push and pull factors that influence e-sports online viewers’ consumption behaviors (N = 1,309) using partial least squares structural equation modeling. The authors proposed a new way to operationalize push and pull factors that have been relatively overlooked in the literature. The findings indicated that, while push and pull factors had different effects on e-sports consumption behaviors, they should be considered equally important in e-sports livestreaming. The study expanded our understanding of the attractiveness and desirability of e-sports and shed some critical light on management and marketing issues within and beyond the e-sports space.

Restricted access

Ansley E. Swann, Rachel R. Kleis and Johanna M. Hoch

Clinical Question: Is there a relationship between resilience and self-reported function in patients who underwent a total joint arthroplasty? Clinical Bottom Line: There is inconsistent, good-quality Level II evidence that investigates the relationship between resilience and self-reported function in patients after joint arthroplasty.

Restricted access

Miranda Rudnick and Brian Wallace

Ankle supports have been shown to reduce ankle injury incidence. Athletes’ use of them may be related to their sport coaches’ beliefs. The purpose of this study was to examine Wisconsin high school boys’ and girls’ basketball coaches’ beliefs regarding ankle support practices. Additional aims were to estimate the percentage of the players who either tape or brace, reveal which sources were used to form coaches’ beliefs about ankle supports, and gain insights regarding how long players are out of play after being injured if they tape, brace, or do not use ankle supports. Chi-squared tests of independence revealed that most coaches neither encouraged nor discouraged ankle supports for their players. A majority of coaches were found to use resources other than scientific-based sources to form their opinions on ankle supports. They also reported that they believed ankle injury return-to-play time was reduced in players who wore ankle supports and that supports did not hinder performance. Coaches should be provided educational opportunities regarding ankle supports so they may provide valid information to help their players make informed decisions.