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1.
The aim of the present study was to evaluate the effects of a 12-week home-based strength, explosive and plyometric (SEP) training on the cost of running (Cr) in well-trained ultra-marathoners and to assess the main mechanical parameters affecting changes in Cr. Twenty-five male runners (38.2?±?7.1 years; body mass index: 23.0?±?1.1?kg·m?2; V˙O2max: 55.4?±?4.0 mlO2·kg?1·min?1) were divided into an exercise (EG?=?13) and control group (CG?=?12). Before and after a 12-week SEP training, Cr, spring-mass model parameters at four speeds (8, 10, 12, 14?km·h?1) were calculated and maximal muscle power (MMP) of the lower limbs was measured. In EG, Cr decreased significantly (p?<?.05) at all tested running speeds (?6.4?±?6.5% at 8?km·h?1; ?3.5?±?5.3% at 10?km·h?1; ?4.0?±?5.5% at 12?km·h?1; ?3.2?±?4.5% at 14?km·h?1), contact time (tc) increased at 8, 10 and 12?km·h?1 by mean +4.4?±?0.1% and ta decreased by ?25.6?±?0.1% at 8?km·h?1 (p?<?.05). Further, inverse relationships between changes in Cr and MMP at 10 (p?=?.013; r?=??0.67) and 12?km·h?1 (p?<?.001; r?=??0.86) were shown. Conversely, no differences were detected in the CG in any of the studied parameters. Thus, 12-week SEP training programme lower the Cr in well-trained ultra-marathoners at submaximal speeds. Increased tc and an inverse relationship between changes in Cr and changes in MMP could be in part explain the decreased Cr. Thus, adding at least three sessions per week of SEP exercises in the normal endurance-training programme may decrease the Cr.  相似文献   

2.
The purpose of the study was to examine the perspectives of both academics and practitioners in relation to forming applied collaborative sport science research within team sports. Ninety-three participants who had previously engaged in collaborative research partnerships within team sports completed an online survey which focused on motivations and barriers for forming collaborations using blinded sliding scale (0–100) and rank order list. Research collaborations were mainly formed to improve the team performance (Academic: 73.6?±?23.3; Practitioner: 84.3?±?16.0; effect size (ES?=?0.54), small). Academics ranked journal articles’ importance significantly higher than practitioners did (Academic: Mrank?=?53.9; Practitioner: 36.0; z?=??3.18, p?=?.001, p?q). However, practitioners rated one-to-one communication as more preferential (Academic: Mrank?=?41.3; Practitioner 56.1; z?=??2.62, p?=?.009, p?q). Some potential barriers were found in terms of staff buy in (Academic: 70.0?±?25.5; Practitioner: 56.8?±?27.3; ES?=?0.50, small) and funding (Academic: 68.0?±?24.9; Practitioner: 67.5?±?28.0; ES?=?0.02, trivial). Both groups revealed low motivation for invasive mechanistic research (Academic: 36.3?±?24.2; Practitioner: 36.4?±?27.5; ES?=?0.01, trivial), with practitioners have a preference towards ‘fast’ type research. There was a general agreement between academics and practitioners for forming research collaborations. Some potential barriers still exist (e.g. staff buy in and funding), with practitioners preferring ‘fast’ informal research dissemination compared to the ‘slow’ quality control approach of academics.  相似文献   

3.
Physiological or performance tests are routinely utilised to assess athletes’ recovery. At present, the ideal tool to assess recovery remains unknown. Therefore, the aim of this systematic review was to examine the change in creatine kinase (CK) and neuromuscular function as measured via a countermovement jump (CMJ) following a match in the contact codes of football. A comprehensive search of databases was undertaken with RevMan (V 5.3) used for statistical analysis. Our results demonstrated that CK pre- versus post-match (standardised mean difference (SMD)?=?0.90, 95% CI?=?0.50 to 1.31, p?p?p?p?=?.03), and pre- versus 24?h post-match (SMD?=??0.80, 95% CI?=??1.31 to ?0.28, p?=?.002) decreased significantly. There was a significant relationship between the change in CK and the change in CMJ PP from immediately pre to immediately post (r?=??0.924, p?=?.025), and between CMJ immediately following a match and 24?h CK change (r?=??0.983, p?=?.017). In conclusion, CK levels increase and performance in the CMJ decreases following a match of a contact code of football. The identification of this relationship may allow coaching staff to implement a standalone measure of recovery.  相似文献   

4.
Irisin is a myokine that is thought to be secreted in response to exercise that may help to prevent obesity and maintain normal glucose metabolism. In this study we investigated the associations between irisin and glucose homeostasis in middle-aged, overweight and obese men (n?= 144) with impaired glucose regulation, and the impact of exercise training on these relationships. The participants underwent 12 weeks of resistance or aerobic (Nordic walking) exercise training three times per week, 60 minutes per session. Venous blood (n?=?105) and skeletal muscle samples (n?=?45) were obtained at baseline and post-intervention. Compared to controls, Nordic walking, but not resistance training, increased irisin levels in plasma (9.6?±?4.2%, P?=?0.014; 8.7?± 4.9%, P?=?0.087; respectively) compared to controls. When considering all subjects, baseline irisin correlated positively with atherogenic index of plasma (r?=?0.244, P?=?0.013) and 2-hour insulin levels (r?=?0.214, P?=?0.028), and negatively with age (r?=??0.262, P?=?0.007), adiponectin (r?=??0.240, P?=?0.014) and McAuley index (r?=??0.259, P?=?0.008). Training-induced FNDC5 mRNA changes were negatively correlated with HbA1c (r?=??0.527, P?=?0.030) in the resistance training group and with chemerin in the Nordic walking group (r?=??0.615, P?=?0.033). In conclusion, 12-weeks of Nordic walking was more effective than resistance training in elevating plasma irisin, in middle-aged men with impaired glucose tolerance. Thus, the change in irisin in response to exercise training varied by the type of exercise but showed limited association with improvements in glucose homeostasis.  相似文献   

5.
The aim of this study was to compare the effects of two different intensity distribution training programmes (polarized (POL) and threshold (THR)) on aerobic performance, strength and body composition variables in ultra-endurance runners. Twenty recreationally trained athletes were allocated to POL (n?=?11; age: 40.6?±?9.7 years; height: 175.4?±?7?cm; weight: 73.5?±?10.8?kg; fat mass 18.4?±?6.0%; VO2max: 55.8?±?4.9?ml/kg/min) or THR group (n?=?9; age: 36.8?±?9.2 years; height: 178.5?±?4.2?cm; weight: 75.5?±?10.4?kg; fat mass 14.9?±?5.3%; VO2max: 57.1?±?5.2?ml/kg/min) and performed the 12 weeks training programme. Both programmes had similar total time and load but a different intensity distribution (POL?=?79.8?±?2.1% in Zone 1; 3.9?±?1.9% in Zone 2; 16.4?±?1.5% in Zone 3; THR?=?67.2?±?4.6% in Zone 1; 33.8?±?4.6% in Zone 2; 0% in Zone 3). Body composition, isokinetic strength and aerobic running performance were measured before and after each programme. Both groups decreased fat mass after training (POL= Δ–11.2%; p?=?.017; ES?=?0.32; THR= Δ–18.8%; p?p?=?0.003; ES?=?0.71) and 12?km/h (Δ–4.5%; p?=?.026; ES?=?0.73) and running time to exhaustion (Δ2.4%; p?=?.011; ES?=?0.33). No changes were observed in strength and no significant differences were observed between the group in any variable. Compared with THR distribution, 12 weeks of POL training efficiently improves aerobic performance in recreational ultra-endurance runners.  相似文献   

6.
The aim of the study was to compare the effect of resistance training (RT) frequencies of five times (RT5), thrice- (RT3) or twice- (RT2) weekly in muscle strength and hypertrophy in young men. Were used a within-subjects design in which 20 participants had one leg randomly assigned to RT5 and the other to RT3 or to RT2. 1?RM and muscle cross-sectional area (CSA) were assessed at baseline, after four (W4) and eight (W8) RT weeks. RT5 resulted in greater total training volume (TTV) than RT3 and RT2 (P?=?.001). 1?RM increased similarly between protocols at W4 (RT5: 55?±?9?Kg, effect size (ES): 1.18; RT3: 51?±?11?Kg, ES: 0.80; RT2: 54?±?7?Kg, ES: 1.13; P?P?2, ES: 0.54; RT3: 22.0?±?4.6?cm2, ES: 0.19; RT2: ES: 0.25; 23.8?±?3.8?cm2; P?2; ES: 0.69; RT3: 23.6?±?4.2?cm2, ES: 0.58; RT2: 25.5?±?3.7?cm2; ES: 0.70; P?2; RT3: 21.2?±?4.0?cm2; RT2: 22.9?±?3.8?cm2). Performing RT5, RT3 and RT2 a week result in similar muscle strength increase and hypertrophy, despite higher TTV for RT5.  相似文献   

7.
Attenuated performance during intense exercise with limited endogenous carbohydrate (CHO) is well documented. Therefore, this study examined whether caffeine (CAF) mouth rinsing would augment performance during repeated sprint cycling in participants with reduced endogenous CHO. Eight recreationally active males (aged 23?±?2?yr, body mass 84?±?4?kg, stature 178?±?7?cm) participated in this randomized, single-blind, repeated-measures crossover investigation. Following familiarization, participants attended two separate evening glycogen depletion sessions. The following morning, participants completed five, 6?s sprints on a cycle ergometer (separated by 24?s active recovery), with mouth rinsing either (1) a placebo solution or (2) a 2% CAF solution. During a fifth visit, participants completed the sprints without prior glycogen depletion. Repeated-measures ANOVA identified significant main effect of condition (CAF, placebo, and control [P?P?P?P?P?P?相似文献   

8.
Training load (TL) and recovery should be in optimal balance to obtain maximal performance gains. We aimed to study sleep as a recovery technique and its relationship with TL and performance in elite athletes. Twenty-six elite female artistic gymnasts were divided into an under 13 (n?=?6), an under 14 (n?=?6), a junior (n?=?7; 14–15y) and a senior (=World Championship (WC) competitors, n?=?7; ≥16y) category. Sleep, through sleep logs, and training parameters, using the session Rate of Perceived Exertion (sRPE) scale, were monitored to calculate total sleep time (TST), sleep efficiency (SE), TL, monotony and strain. Performance of WC competitors was evaluated through coach and WC qualification ranking. For the entire group, TST (effect sizes (ES)?=??1.12, confidence intervals (CI)?=??60:?47, P?P?=?.022) were shorter during week than weekend nights. TST and SE were highest in youngest gymnasts (P?P?P?P?P?=?.030). TST correlated with coach ranking (r?=??0.857, P?=?.014). Higher TL correlated with worse WC (r?=?0.829, P?=?.042) and coach (r?=?0.893, P?=?.007) ranking. This research in elite gymnasts indicated associations between decreased TST, augmented TL and inferior performance. Optimizing sleep and TL may therefore represent strategies to enhance performance.  相似文献   

9.
Abstract

The objective of this study was to determine the relationship between different variables measured with a force plate during the swimming start push-off phase and start performance presented by times to 5, 10 and 15?m. Twenty-one women from the Slovenian national swimming team performed two different swim starts (freestyle and undulatory) on a portable force plate to a distance further than 15?m. Correlations between push-off variables and times to 5, 10 and 15?m were quantified through Pearson's product-moment correlation coefficient (r). The variables that significantly correlated (p?<?.05) to all times measured in the two starts performed were: average horizontal acceleration (freestyle: r?=??0.58 to ?0.71; and undulatory: r?=??0.55 to ?0.66), horizontal take-off velocity (freestyle: r?=??0.56 to ?0.69; and undulatory: r?=??0.53 to ?0.67) and resultant take-off velocity (freestyle: r?=??0.53 to ?0.65; and undulatory: r?=??0.52 to ?0.61). None of the variables derived from the vertical force were correlated to swimming start performance (p?>?.05). Based on the results of this study, we can conclude that horizontal take-off velocity and average horizontal acceleration (calculated as the average horizontal force divided by swimmer's body mass) are the variables most related to swimming start performance in experienced swimmers, and therefore could be the preferred measures to monitor swimmers’ efficiency during the push-off phase.  相似文献   

10.
This study investigated how learning a passing skill with futsal or soccer task constraints influenced transfer to a new task. Futsal (n?=?24, 13.6?±?1.2 years old, 7.0?±?1.6 years of experience) and soccer (n?=?24, 13.6?±?1.2 years old, 6.8?±?1.2 years of experience) players performed two 5v5?+?goalkeeper modified games – a futsal-like task (small playing area with the futsal ball) and soccer-like task (large playing area with the soccer ball). Participants’ passing accuracy and their orientation of attention were assessed during the two tasks. The futsal group improved their passing accuracy (ES?=?0.75?±?0.61) from the futsal-like to the soccer-like task, and they were more accurate than soccer players (ES?=?2.98?±?2.96). Conversely, the soccer group’s passing accuracy remained stable across the two tasks (ES?=?0.10?±?0.52) and it was similar to the futsal group in the futsal-like task (ES?=?0.58?±?1.93). This indicates a higher magnitude of transfer (and adaptability) from performing passes in a small playing area with short time to act – futsal task constraints – to a larger playing area with longer time – soccer task constraints – than vice-versa. Furthermore, the futsal group showed a higher adaptation of attention orientation to the affordances that emerged with the soccer task constraints, which is suggested to be one of the main mechanisms promoting skill transfer. These results encourage soccer practitioners to introduce futsal task constraints to fast-track players’ ability to functionally adapt perception–action coupling.  相似文献   

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