Surprisingly little attention has been devoted to the role played by the intrinsic muscles of the human foot. The aim of this study was to quantify the capabilities of the flexor digitorum brevis (FDB) muscle to contribute to upright postural control. The approaches consisted of analysis of the effects of FDB contraction elicited by external electrical stimulation and quantification of the magnitude of FDB torque generation. The results showed the FDB can produce significant changes in static posture by itself as shown by changes in the center of pressure. Moreover, the FDB contribution to counterbalance the gravity’s toppling force was estimated at around 14.5% of the total required active torque at the ankle to keep the subject from falling. A posteriori functional analysis during horizontal perturbations showed high and self-sustained activity of FDB. These results demonstrated that the FDB has a significant capability of contributing to postural control.
Liria Akie Okai and André Fabio Kohn
Anita L. Stewart
The term “community-based” can refer to many types of physical activity interventions. The bulk of physical activity research in older adults focuses on changing individual behavior, sometimes in community settings. Addressing the nation’s goal of increasing the proportion of physically active older adults requires more programs to improve contextual factors that support individual behavior and calls for introducing into community settings successful individual-level programs based on solid research. The social ecology model provides an ideal multilevel framework for community-wide efforts. In conjunction with programs to increase the types and levels of physical activity of older adults, changes can be directed at social, cultural, environmental, institutional, and policy contexts for individual behavior change. Guidelines and evaluation methods, including cost analysis of developing, implementing, and sustaining programs, are needed. Recommendations are made to advance community-based strategies for promoting physical activity among adults age 50 and older.
Neil M. Johannsen and Rick L. Sharp
The purpose of this study was to investigate differences in substrate oxidation between dextrose (DEX) and unmodified (UAMS) and acid/alcohol-modified (MAMS) cornstarches. Seven endurance-trained men (VO2peak = 59.1 ± 5.4 mL·kg−1·min−1) participated in 2 h of exercise (66.4% ± 3.3% VO2peak) 30 min after ingesting 1 g/kg body weight of the experimental carbohydrate or placebo (PLA). Plasma glucose and insulin were elevated after DEX (P < 0.05) compared with UAMS, MAMS, and PLA. Although MAMS and DEX raised carbohydrate oxidation rate through 90 min of exercise, only MAMS persisted throughout 120 min (P < 0.05 compared with all trials). Exogenous-carbohydrate oxidation rate was higher in DEX than in MAMS and UAMS until 90 min of exercise. Acid/alcohol modification resulted in augmented carbohydrate oxidation with a small, sustained increase in exogenous-carbohydrate oxidation rate. MAMS appears to be metabolizable and available for oxidation during exercise.
Michelle M. Porter, Miriam E. Nelson, Maria A. Fiatarone Singh, Jennifer E. Layne, Christine M. Morganti, Isaiah Trice, Christina D. Economos, Ronenn Roubenoff and William J. Evans
Resistance training (RT) increases strength in older adults, but there have been few studies of long-term RT or detraining in older adults. Postmenopausal participants (51–71 years of age) were randomized to RT or a control group for Year 1. For Year 2, participants chose whether to resistance train or not. Three groups emerged: train/train (n = 8: 60 ± 4 years), train/no train (n = 11: 62 ± 3 years), or controls (n = 17; 58 ± 6 years). Both training groups increased strength (p < .05) in Year 1. In Year 2, train/train maintained strength, whereas train/no train lost strength for knee extension (p < .001) but not for arm pulldown. Controls did not change. Reported physical activity levels were significantly increased in trainers in Year 1 and remained high regardless of RT in Year 2 (p < .05). Therefore, sustained changes in strength and physical activity behavior might be possible even if RT is discontinued.
Michael D. Ferrell, Robert L. Beach, Nikolaus M. Szeverenyi, Marlyn Krch and Bo Fernhall
Performance at one's highest personal level is often accompanied by a palpable, yet enigmatic sensation that many athletes refer to as the zone. Competitive athletes regularly acknowledge that their top performances are dependent on achieving a zone state of performance. Functional magnetic resonance imaging (fMRI) technologies were used in observing differing patterns of neural activation that occur among athletes during a hypnotically recalled zone-state performance of eight accomplished, competitive right-handed archers. These data were compared to each participant's respective fMRI data of a hypnotically assisted recall of a normal performance. Analysis of composite group data revealed significant (p = 0.05) neural activation of zone performance (ZP) over normal performance (NP), suggesting that performance in a zone state involves identifiable characteristics of neural processing. Perhaps this investigation might stimulate additional, more creative research in identifying a psychophysiological indicator of the zone phenomenon that would provide adequate justification for a training regimen providing a more reliable and sustained zone performance.
Emmanuel Jacobs, Nathalie Roussel, Ine Van Caekenberghe, Edith Cassiers, Luc Van den Dries, Jonas Rutgeerts, Jan Gielen and Ann Hallemans
This cross-sectional study aimed at developing a biomechanical method to objectify voluntary and unpredictable movements, using an automated three-dimensional motion capture system and surface electromyography. Fourteen experienced theater performers were tested while executing the old man exercise, wherein they have to walk like an old man, building up a sustained high intensive muscular activity and tremor. Less experienced performed showed a different kinematics of movement, a slower speed of progression and more variable EMG signals at higher intensity. Female performers also differed from males in movement kinematics and muscular activity. The number of the trial only influenced the speed of progression. The performers showed results which could be well placed within the stages of learning and the degrees of freedom problem.
Heather R. Clark, Margo E. Barker and Bernard M. Corfe
Mountain marathons are 2-d, self-supported adventure races, during which competitors must carry all nutritional requirements to sustain athletic effort. This requires a compromise between the energy required to perform and the weight penalty of carrying it. We have undertaken a nutritional survey of event competitors in the UK using a questionnaire-based approach and have monitored dehydration during the event. We found that competitors in longer-distance classes (> 50 km) carry significantly less mass of food, which is more energy dense, but that the calorific value is lower than that of competitors in shorter classes. Carbohydrate and protein consumption both positively associated with performance. Competitors became progressively dehydrated throughout the event. Counterintuitively, the better-performing subjects became the most dehydrated. Competitors at all distances should make more effort to rehydrate during breaks in the event. Competitors at shorter distances could choose more energy-dense foods to reduce weight penalty.
Wendy J. Brown, Kerry Mummery, Elizabeth Eakin and Grant Schofield
To describe the effectiveness of a multi-strategy physical activity (PA) intervention.
Self-report data from random samples were collected prior to and following intervention. Social marketing, healthcare provider, and environmental strategies were concurrently implemented with a central coordinating theme of “10,000 Steps Rockhampton.”
There was evidence of significant project reach and awareness. The downward trend in PA seen in the comparison community (48.3% to 41.9% “active”) was not evident in Rockhampton. Women were the “early adopters” in this project; with an increase of 5% (95% CI: –0.6, 10.6) in the percent categorized as “active” (compared with decreases among women in the comparison community and among men in both communities).
High levels of project awareness, combined with modest increases in activity levels in women, demonstrate initial project effects. Longer term interventions, focusing on sustainable individual, social, and environmental change strategies are needed to maintain and improve this result.
Ying Hwa Kee, Nikos N.L.D. Chatzisarantis, Pui Wah Kong, Jia Yi Chow and Lung Hung Chen
We examined whether the momentary induction of state mindfulness benefited subsequent balance performance, taking into consideration the effects of dispositional mindfulness. We also tested whether our mindfulness induction, grounded in sustaining moment-to-moment attention, influenced the attentional focus strategies that were adopted by the participants during the balancing task. Balance performance was ascertained based on approximate entropy (ApEn) of the center of pressure (COP) data. The study involved 32 males (age: M = 22.8, SD = 1.94) who were randomly assigned to the mindfulness or control group. Using difference in pretest to posttest performance based on the medio-lateral movements as the dependent variable, the test for interaction showed that the mindfulness induction was more effective for participants with higher dispositional mindfulness. Participants who underwent mindfulness induction also reported greater use of external focus strategies than those in the control group. Results suggest that momentary mindful attention could benefit balance performance and affect the use of attentional focus strategies during movement control.
Erica L. Carleton, Julian Barling, Amy M. Christie, Melissa Trivisonno, Kelsey Tulloch and Mark R. Beauchamp
Based on the contention that leadership has sustained effects on followers even after the leader–follower relationship has ended, we investigated the career-long effects of abusive coach leadership on athlete aggression and task performance. Abusive leadership scores were derived from ratings by two independent raters’ evaluations of coaches’ biographies, and athlete aggression and task performance data were derived from objective sources. Data were obtained from players (N = 693) and coaches (N = 57) involved in the National Basketball Association (NBA) between the 2000–2001 and 2005–2006 seasons. Controlling for tenure, salary, team winning percentage, and absence due to injuries, multilevel modeling showed that exposure to abusive leadership influenced both the trajectory of psychological aggression and task performance over players’ careers. These findings suggest that the effects of abusive leadership extend far longer than currently acknowledged, thus furthering our understanding of the nature and effects of abusive leadership.