to produce the ground reaction forces needed to support the body against gravity, propel the body forward, and maintain stability during gait. 12 , 13 Consequently, a number of studies have shown that thresholds of muscle strength can be used for early identification of older adults at high risk of
Mary Hellen Morcelli, Dain Patrick LaRoche, Luciano Fernandes Crozara, Nise Ribeiro Marques, Camilla Zamfolini Hallal, Mauro Gonçalves and Marcelo Tavella Navega
Daniel Lock, Tracy Taylor, Daniel Funk and Simon Darcy
Stephen Reysen, Jamie S. Snider and Nyla R. Branscombe
We examined the effect of corporate renaming of a stadium on fans’ felt anger and perceived harm to the team’s distinctiveness by asking participants to imagine that their historic local sport venue was renamed (or not) after a large corporation or a wealthy individual. Participants reported more perceived harm to the team’s distinctiveness when a corporation (vs. individual) donated money to the team. Furthermore, participants who thought that the venue name had been changed (compared with no name change) expressed more anger and perceived the name change to be a threat to the team’s distinctiveness. A mediated moderation analysis showed that, compared with when the stadium name remained the same, highly identified fans believed the name change would harm the distinctiveness of the team, which resulted in greater felt anger. In line with social identity theory, the results show that anger is an emotional outcome of recently experienced distinctiveness threat.
Darlene A. Kluka and Anneliese Goslin
P. Monica Chien, Sarah J. Kelly and Clinton S. Weeks
We conducted an experiment to investigate the impact of sport scandal on consumer attitudes toward a range of sport stakeholders. We examined the effects of fans’ social identity (fan of scandalized team vs. fan of rival team), scandal severity (single perpetrator vs. multiple perpetrators), and the sponsor brand’s response to the scandal (sponsorship retention vs. termination) on consumers’ attitudes toward the implicated team, the scandal perpetrators, the sport, and sponsor brand. We find evidence of differential reactions to scandal reflecting social identity, such that fans support their own team despite increased scandal severity but negatively judge a rival team’s transgressions. Results suggest that where fans are concerned, sponsors may be better served to continue with a sponsorship following scandal than to terminate, even for some forms of severe scandal. However, termination may receive more positive evaluation from rival team fans; hence continuation of sponsorship needs to accompany a tempered approach.
LeRoy W. Alaways, Sean P. Mish and Mont Hubbard
Pitched-baseball trajectories were measured in three dimensions during competitions at the 1996 Summer Olympic games using two high-speed video cameras and standard DLT techniques. A dynamic model of baseball flight including aerodynamic drag and Magnus lift forces was used to simulate trajectories. This simulation together with the measured trajectory position data constituted the components of an estimation scheme to determine 8 of the 9 release conditions (3 components each of velocity, position, and angular velocity) as well as the mean drag coefficient CD and terminal conditions at home plate. The average pitch loses 5% of its initial velocity during flight. The dependence of estimated drag coefficient on Reynolds number hints at the possibility of the drag crisis occurring in pitched baseballs. Such data may be used to quantify a pitcher’s performance (including fastball speed and amount of curve-ball break) and its improvement or degradation over time. It may also be used to understand the effects of release parameters on baseball trajectories.
Amber E. Rowell, Robert J. Aughey, Will G. Hopkins, Andrew M. Stewart and Stuart J. Cormack
Objective measures of recovery from football match play could be useful for assessing athletes’ readiness to train, if sensitive to preceding match load.
To identify the sensitivity of countermovement-jump (CMJ) performance and concentration of salivary testosterone and cortisol relative to elite football match load.
CMJ performance and salivary hormones were measured in 18 elite football players before (27, 1 h) and after (0.5, 18, 42, 66, 90 h) 3 consecutive matches. Match load was determined via accelerometer-derived PlayerLoad and divided into tertiles. Sensitivity of CMJ performance and hormone concentrations to match load was quantified with t statistics and magnitude-based inferences (change in mean as % ± 90% confidence interval) derived with a linear mixed model.
Jump height was reduced in medium and high load at 0.5 h (10% ± 7% and 16% ± 8%) and 18 h (7% ± 4% and 9% ± 5%) postmatch. There was a 12% ± 7% reduction in ratio of flight time to contraction time (FT:CT) in high load at 0.5 h post, with reductions in medium and high load at 18 h. Reductions in FT:CT persisted at later postmatch time points than changes in jump height. Increased cortisol (range 55–165%) and testosterone (range 17–20%) were observed in all match loads at 0.5 h post, with individual variability thereafter.
Measures of CMJ performance and hormonal concentrations were sensitive to levels of A League football match load. Although jump height was reduced immediately postmatch, FT:CT provided a more sensitive measure of recovery. Football match play induces an acute hormonal response with substantial individual variability thereafter.
Julien Morlier, Michel Mesnard and Mariano Cid
The development of composite material poles since 1960 has played a prominent part in performance improvement in pole-vaulting. Previous studies devoted to pole-vaulting models were based on constant mechanical characteristics. It is thus necessary to identify the local bending rigidities of the pole to build realistic pole-vaulting models. Updating methods developed for dynamic structure studies allow us to describe local mechanical characteristics. These methods are based on the comparison between experimental results and those determined numerically by finite element models. This study presents an adaptation of these methods to determine the local bending rigidities of the pole. The updating technique is validated by a deflection test of a homogeneous beam. Then, a study of the model sensitivity is carried out to investigate the procedure robustness. Finally, the updating method is applied to an old design pole and to a recent one. The results obtained vary greatly from one pole to the other; they highlight the evolutions in pole design.
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.