to the studied interventions. 14 Athletes were told that omitting intensity bouts from their warm-ups 20 to 40 minutes before their race 16 – 18 could potentially negatively affect their performance 16 and lead to false conclusions in the current research project. After testing, all athletes
Philippe Richard and François Billaut
Júlio A. Costa, João Brito, Fábio Y. Nakamura, Eduardo M. Oliveira and António N. Rebelo
, especially during the first sleeping hours. However, late-night soccer training does not seem to affect SWSE and “hour-by-hour” HRV indices in comparison with rest days. These findings may indicate that these methods are not sensitive enough to detect the overnight cardiac autonomic activity disturbances
James O. Hill and Reneé Commerford
In this paper, we review the impact of physical activity on energy and maeronutrient balances. Stability of body weight and body composition depends on reaching a steady-state where the amount and composition of energy ingested are equal to the amount and composition of energy expended. We describe how a person's level of physical activity can have a significant impact on determining the level of body weight and body fatness at which that steady-state is reached. First, physical activity can directly affect both total energy intake and total energy expenditure. Physical activity can also affect fat balance, and it is becoming clear that imbalances in total energy are largely imbalances in fat. High levels of physical activity should help individuals reach fat and energy balances at lower levels of body fatness than would have been achieved at lower levels of physical activity.
Allen C. Parcell, Melinda L. Ray, Kristine A. Moss, Timothy M. Ruden, Rick L. Sharp and Douglas S. King
Previous investigations have reported that soluble fiber reduces the plasma glucose and insulin changes after an oral glucose load. To improve the payability of a soluble-fiber feeding, this study addressed how a combined, soluble fiber (delivered in capsule form) and a preexercise CHO feeding would affect metabolic responses during exercise. On 3 different days, participants ingested a placebo (CON), 75 g liquid CHO (GLU), or 75 g liquid CHO with 14.5 g encapsulated guar gum (FIB) 45 min before cycling for 60 min at 70% VO2peak. Peak concentrations of plasma glucose and insulin were similar and significantly greater than CON preexercise (p < .05). Similarities in carbohydrate reliance were observed in GLU and FIB. Muscle glycogen use did not differ significantly among trials. These results demonstrate that encapsulated soluble fiber delivered with a liquid CHO feeding does not affect plasma glucose, insulin, or muscle glycogen utilization during exercise.
Lorcan D. Cronin and Justine B. Allen
The present study explored the relationships between the coaching climate, youth developmental experiences (personal and social skills, cognitive skills, goal setting, and initiative) and psychological well-being (self-esteem, positive affect, and satisfaction with life). In total, 202 youth sport participants (Mage = 13.4, SD = 1.8) completed a survey assessing the main study variables. Findings were consistent with Benson and Saito’s (2001) framework for youth development. In all analyses, the coaching climate was related to personal and social skills, cognitive skills, goal setting, and initiative. Mediational analysis also revealed that the development of personal and social skills mediated the relationships between the coaching climate and all three indices of psychological well-being (self-esteem, positive affect, and satisfaction with life). Interpretation of the results suggests that coaches should display autonomy-supportive coaching behaviors because they are related to the developmental experiences and psychological well-being of youth sport participants.
Research has demonstrated that coaches experience stress because of the nature of their job and that stress can affect their physical and mental well-being (Richman, 1992; Wang & Ramsey, 1998). The purpose of the present study was to better understand coaches’ experiences with stress, the perceived effects of stress on their coaching performance, and their coping strategies. A semistructured interview approach was used with 10 NCAA Division I male and female head coaches. The five major themes that characterized the coaches’ experiences were contextual/conditional factors, sources of stress, responses and effects of stress, managing stress, and sources of enjoyment. The results are discussed in relation to Smith’s (1986) cognitive-affective model of stress. Opportunities for future research are suggested, and implications for practitioners who want to help coaches manage the stress of their profession are offered.
Donetta J. Cothran and Pamela Hodges Kulinna
It was the purpose of this study to examine students’ perspectives on three teaching strategies. Seventy middle school students were interviewed, and they rank ordered the strategies. A constant comparison process guided the interview data analysis, while the rank order data were analyzed via descriptive statistics and a Friedman Analysis of Variance by Ranks. Two key concepts that influenced students’ perspectives on the effectiveness of the teaching strategies were their conceptions of the affective dimensions of each strategy and their knowledge beliefs.
Mark R. Stone, Alan St Clair Gibson and Kevin G. Thompson
Exercise is known to result in hemodynamic changes in the bilateral prefrontal cortex. The aim of this study was to investigate hemodynamic changes in right and left hemispheres of the prefrontal cortex (PFC) during incremental cycling exercise.
After 10 min rest, 9 participants (mean age 26.6 ± 2.5 y, mass 77.5 ± 9.7 kg, stature 1.79 ± 0.9 m) cycled at 100–150 W for 4 min. Thereafter, resistance was increased by 25 W every 4 min until exhaustion (EXH). Respiratory exchange and concentrations of oxy- ([HbO2]), deoxy- ([(HHb]), and total hemoglobin ([Hbtot]) in the PFC were continuously measured. Data were averaged for 60 s at rest and preceding ventilatory threshold 1 (VT1), VT2, and volitional EXH and after 5 min recovery. Subjective ratings of affect were measured at VT1, VT2, VT1 minus 25 W (VT1-25W), and VT2 plus 25 W (VT2+25W).
There were no between-hemispheres differences in [HbO2] or [Hbtot] at rest, VT1, or recovery or in [HHb] at any point. Right-hemisphere [HbO2] and [Hbtot] were significantly greater than left at VT2 (P = .01 and P = .02) and EXH (P = .03 and P = .02). Affect was significantly greater at VT1-25W vs VT2 and VT2+25W and at VT1 and VT2 vs VT2+25W (P < .01–.03).
To the authors’ knowledge, this is the first study to describe an exercise-state-dependent change in PFC asymmetry during incremental exercise. The asymmetry detected coincided with a decrease in affect scores in agreement with the PFC-asymmetry hypothesis.
Matthew C. Varley, Arne Jaspers, Werner F. Helsen and James J. Malone
Sprints and accelerations are popular performance indicators in applied sport. The methods used to define these efforts using athlete-tracking technology could affect the number of efforts reported. This study aimed to determine the influence of different techniques and settings for detecting high-intensity efforts using global positioning system (GPS) data.
Velocity and acceleration data from a professional soccer match were recorded via 10-Hz GPS. Velocity data were filtered using either a median or an exponential filter. Acceleration data were derived from velocity data over a 0.2-s time interval (with and without an exponential filter applied) and a 0.3-second time interval. High-speed-running (≥4.17 m/s2), sprint (≥7.00 m/s2), and acceleration (≥2.78 m/s2) efforts were then identified using minimum-effort durations (0.1–0.9 s) to assess differences in the total number of efforts reported.
Different velocity-filtering methods resulted in small to moderate differences (effect size [ES] 0.28–1.09) in the number of high-speed-running and sprint efforts detected when minimum duration was <0.5 s and small to very large differences (ES –5.69 to 0.26) in the number of accelerations when minimum duration was <0.7 s. There was an exponential decline in the number of all efforts as minimum duration increased, regardless of filtering method, with the largest declines in acceleration efforts.
Filtering techniques and minimum durations substantially affect the number of high-speed-running, sprint, and acceleration efforts detected with GPS. Changes to how high-intensity efforts are defined affect reported data. Therefore, consistency in data processing is advised.
Craig A. Horswill
As a result of exercise-induced sweating, athletes and trained individuals can lose up to 3 L of fluid per hour. Fluid replacement is required to maintain hydration and allow the athlete to continue to perform. Inadequate fluid intake will adversely affect temperature regulation, cardiovascular function, and muscle metabolism. To maximize fluid intake and effectively replace fluid, athletes must employ behavioral strategies. Athletes can also select beverages with characteristics that complement their behavioral efforts. Palatability, rapid absorption, retention of the fluid, and ergogenicity are the major attributes to consider for enhancing hydration during training and physical activity.