Promoting physical activity using a wearable activity tracker in college students: A cluster randomized controlled trial

This study examined the effects of utilizing a wearable activity tracker in a credit-based physical activity instructional program (PAIP) for promoting physical activity (PA) in college students. Fourteen PAIP courses in a large public university were randomly assigned into intervention (k = 7; n = 101) and control (k = 7; n = 86) groups. All courses focused on a core curriculum that covers basic exercise and behavioral science contents through lectures and activity sessions. A Misfit Flash activity tracker was provided to students in the intervention group. Objective PA assessments occurred at baseline, mid-, and end-of-semester during a 15-week academic semester. The control group showed a significant reduction in moderate- and vigorous-intensity PA (MVPA) minutes from baseline to the end-of-semester (P <.05), whereas the intervention group showed no changes in MVPA minutes over time. However, the intervention group also showed increased sedentary time and decreased time spent in light-intensity PA during the intervention period. Taken together, the present study found null effects of utilizing the wearable activity tracker in promoting PA in college students suggesting that intervention of primary using the wearable activity tracker as a behavior change strategy may not be effective to increase in PA in this setting.     

Dietary nitrate supplementation does not improve cycling time-trial performance in the heat

This investigation examined the effect of beetroot juice (BR) supplementation, a source of dietary nitrate (NO₃^?), on cycling time-trial (TT) performance and thermoregulation in the heat. In a double-blind, repeated-measures design, 12 male cyclists (age 26.6 ± 4.4 years, VO_2peak 65.8 ± 5.5 mL.kg^?1.min^?1) completed four cycling TTs (14 kJ.kg^?1) in hot (35°C, 48% relative humidity) and euthermic (21°C, 52%) conditions, following 3 days supplementation with BR (6.5 mmol NO₃^? for 2 days and 13 mmol NO₃^? on the final day), or NO₃^–depleted placebo (PLA). Salivary NO₃^? and nitrite, core (T_c) and mean skin temperature (T_sk) were measured. Salivary NO₃^? and nitrite increased significantly post-BR supplementation (p < 0.001). Average TT completion time (mm:ss) in hot conditions was 56:50 ± 05:08 with BR, compared with 58:30 ± 04:48 with PLA (p = 0.178). In euthermic conditions, average completion time was 53:09 ± 04:35 with BR, compared with 54:01 ± 04:05 with PLA (p = 0.380). The TT performance decreased (p < 0.001), and T_c (p < 0.001) and T_sk (p < 0.001) were higher in hot compared with euthermic conditions. In summary, BR supplementation has no significant effect on cycling TT performance in the heat.     

Injuries in formal and informal non-professional soccer – an overview of injury context,causes, and characteristics

The objective of this study is to analyse context, causes, and characteristics of injuries in non-professional soccer. Therefore, a retrospective telephone survey was carried out with persons who were injured while playing soccer and who reported this accident to the Swiss National Accident Insurance Fund (Suva). Based on these data, an analysis of 708 soccer injuries was performed. The findings show that 30.1% of the injuries occurred during informal soccer play, and 75.4% of the injured persons were soccer club members. 53.0% of all injuries were caused by contact and 29.5% by foul play. Foul play was not associated with injury severity. With respect to injury severity, twisting/turning and being tackled by an opponent were identified as the most influental injury causes. Moreover, the risk of being severely injured was particularly high players of the 30+/40+ amateur leagues. In conclusion, the findings highlight that 30+/40+ league players are a major target group for the prevention of severe soccer injuries. Soccer clubs may constitute an appropriate multiplier for implementing prevention strategies such as fair play education, healthy play behaviours, and prevention programmes. Finally, a better understanding of injury situations leading to severe injuries is needed to improve injury prevention.     

Gender,Sexuality, and Sport in America

Sex, Violence & Power in Sports: Rethinking Masculinity by Michael A, Messner and Donald F. Sabo (Freedom, CA: The Crossing Press, 1994)

Coming on Strong: Gender and Sexuality in Twentieth-Century Women's Sport by Susan Cahn (New York: The Free Press, 1994)     

Time–motion analysis of elite field hockey,with special reference to repeated-sprint activity

Limited information exists about the movement patterns of field-hockey players, especially during elite competition. Time–motion analysis was used to document the movement patterns during an international field-hockey game. In addition, the movement patterns of repeated-sprint activity were investigated, as repeated-sprint ability is considered to be an important fitness component of team-sport performance. Fourteen members of the Australian men's field-hockey team (age 26±3 years, body mass 76.7±5.6?kg, [Vdot]O_2max 57.9±3.6?ml?·?kg^?1?·?min^?1; mean±s) were filmed during an international game and their movement patterns were analysed. The majority of the total player game time was spent in the low-intensity motions of walking, jogging and standing (46.5±8.1, 40.5±7.0 and 7.4±0.9%, respectively). In comparison, the proportions of time spent in striding and sprinting were 4.1±1.1 and 1.5±0.6%, respectively. Our criteria for ‘repeated-sprint’ activity (defined as a minimum of three sprints, with mean recovery duration between sprints of less than 21?s) was met on 17 occasions during the game (total for all players), with a mean 4±1 sprints per bout. On average, 95% of the recovery during the repeated-sprint bouts was of an active nature. In summary, the results suggest that the motion activities of an elite field-hockey competition are similar to those of elite soccer, rugby and Australian Rules football. In addition, the investigation of repeated-sprint activity during competition has provided additional information about the unique physiological demands of elite field-hockey performance.     

Reliability and validity of different methods of estimating the one-repetition maximum during the free-weight prone bench pull exercise

ABSTRACT

This study examined the reliability and validity of three methods of estimating the one-repetition maximum (1RM) during the free-weight prone bench pull exercise. Twenty-six men (22 rowers and four weightlifters) performed an incremental loading test until reaching their 1RM, followed by a set of repetitions-to-failure. Eighteen participants were re-tested to conduct the reliability analysis. The 1RM was estimated through the lifts-to-failure equations proposed by Lombardi and O’Connor, general load-velocity (L-V) relationships proposed by Sánchez-Medina and Loturco and the individual L-V relationships modelled using four (multiple-point method) or only two loads (two-point method). The direct method provided the highest reliability (coefficient of variation [CV] = 2.45% and intraclass correlation coefficient [ICC] = 0.97), followed by the Lombardi’s equation (CV = 3.44% and ICC = 0.94), and no meaningful differences were observed between the remaining methods (CV range = 4.95–6.89% and ICC range = 0.81–0.91). The lifts-to-failure equations overestimated the 1RM (3.43–4.08%), the general L-V relationship proposed by Sánchez-Medina underestimated the 1RM (?3.77%), and no significant differences were observed for the remaining prediction methods (?0.40–0.86%). The individual L-V relationship could be recommended as the most accurate method for predicting the 1RM during the free-weight prone bench pull exercise.     

Effect of sand versus grass training surfaces during an 8-week pre-season conditioning programme in team sport athletes

Abstract

This study compared the use of sand and grass training surfaces throughout an 8-week conditioning programme in well-trained female team sport athletes (n = 24). Performance testing was conducted pre- and post-training and included measures of leg strength and balance, vertical jump, agility, 20 m speed, repeat speed (8 × 20 m every 20 s), as well as running economy and maximal oxygen consumption (VO_2max). Heart rate (HR), training load (rating of perceived exertion (RPE) × duration), movement patterns and perceptual measures were monitored throughout each training session. Participants completed 2 × 1 h conditioning sessions per week on sand (SAND) or grass (GRASS) surfaces, incorporating interval training, sprint and agility drills, and small-sided games. Results showed a significantly higher (P < 0.05) HR and training load in the SAND versus GRASS group throughout each week of training, plus some moderate effect sizes to suggest lower perceptual ratings of soreness and fatigue on SAND. Significantly greater (P < 0.05) improvements in VO_2max were measured for SAND compared to GRASS. These results suggest that substituting sand for grass training surfaces throughout an 8-week conditioning programme can significantly increase the relative exercise intensity and training load, subsequently leading to superior improvements in aerobic fitness.     

The Influence of Aging on Power and Endurance in Man

Abstract

The purpose of this study was to examine the strength-decrement fatigue effects in 14 muscle groups of the trunk and lower extremities resulting from a sub-maximal treadmill run at seven miles per hour for a period of ten minutes on a horizontal plane. Only two muscle groups, the hip outward rotators and the trunk flexors, were fatigued sufficiently to cause a significant strength decrement; a third muscle group, the knee flexors, had a loss in mean strength which approached the .05 level of confidence.     

无边界高等教育及其资格认证

在全球化背景下 ,特别是世贸组织的发展 ,高等教育已越来越被视为一种国际商品和服务贸易中的出口产业。各国积极谋求开拓高等教育的国际市场 ,吸引海外学生 ,在别国开办和接管高校 ,运用信息与传播技术实施远程高等教育 ,从而出现了无边界高等教育。无边界高等教育的发展 ,在较大程度上依赖于教育质量的保障和受教育者的资格认证 ,因而有效发展国际认可的资格认证制度 ,将是无边界高等教育发展的一个重要方面