Jonathan Leeder

Sleep duration and quality in elite athletes measured using wristwatch actigraphy

Abstract Sleep is known to be an important component of recovery from training, yet little is known about the quality and quantity of sleep achieved by elite athletes. The aim of the present study was to quantify sleep in elite athletes using wristwatch actigraphy. Individual nights of sleep from a cohort of Olympic athletes (n = 47) from various sports were analysed and compared to non-athletic controls (n = 20). There were significant differences between athletes and controls in all measures apart from ‘time asleep’ (p = 0.27), suggesting poorer characteristics of sleep in the athlete group. There was a significant effect of gender on ‘time awake’ (mean difference: 12 minutes higher in males; 95% likely range: 3 to 21 minutes) and ‘sleep efficiency’ (mean difference: 2.4 lower in males; 95% likely range: 0.1 to 4.8). Athletes showed poorer markers of sleep quality than an age and sex matched non-athletic control group (Sleep efficiency: 80.6 ± 6.4% and 88.7 ± 3.6%, respectively. Fragmentation Index: 36.0 ± 12.4 and 29.8 ± 9.0, respectively) but remained within the range for healthy sleep. This descriptive study provides novel data for the purpose of characterising sleep in elite athletes.

Compression garments and recovery from exercise-induced muscle damage: a meta-analysis

The purpose of the study was to determine the effects of compression garments on recovery following damaging exercise. A systematic review and meta-analysis was conducted using studies that evaluated the efficacy of compression garments on measures of delayed onset muscle soreness (DOMS), muscular strength, muscular power and creatine kinase (CK). Studies were extracted from a literature search of online databases. Data were extracted from 12 studies, where variables were measured at baseline and at 24 or 48 or 72 h postexercise. Analysis of pooled data indicated that the use of compression garments had a moderate effect in reducing the severity of DOMS (Hedges’ g=0.403, 95% CI 0.236 to 0.569, p<0.001), muscle strength (Hedges’ g=0.462, 95% CI 0.221 to 0.703, p<0.001), muscle power (Hedges’ g=0.487, 95% CI 0.267 to 0.707, p<0.001) and CK (Hedges’ g=0.439, 95% CI 0.171 to 0.706, p<0.001). These results indicate that compression garments are effective in enhancing recovery from muscle damage.

Recovery and Adaptation From Repeated Intermittent-Sprint Exercise

PURPOSE This investigation aimed to ascertain a detailed physiological profile of recovery from intermittent-sprint exercise of athletes familiar with the exercise and to investigate if athletes receive a protective effect on markers of exercise-induced muscle damage (EIMD), inflammation, and oxidative stress after a repeated exposure to an identical bout of intermittent-sprint exercise. METHODS Eight well-trained male team-sport athletes of National League or English University Premier Division standard (mean ± SD age 23 ± 3 y, VO2max 54.8 ± 4.6 mL ·kg-1 · min-1) completed the Loughborough Intermittent Shuttle Test (LIST) on 2 occasions, separated by 14 d. Maximal isometric voluntary contraction (MIVC), countermovement jump (CMJ), creatine kinase (CK), C-reactive protein (CRP), interleukin-6 (IL-6), F2-isoprostanes, and muscle soreness (DOMS) were measured before and up to 72 h after the initial and repeated LISTs. RESULTS MIVC, CMJ, CK, IL-6, and DOMS all showed main effects for time (P < .05) after the LIST, indicating that EIMD was present. DOMS peaked at 24 h after LIST 1 (110 ± 53 mm), was attenuated after LIST 2 (56 ± 39 mm), and was the only dependent variable to demonstrate a reduction in the second bout (P = .008). All other markers indicated that EIMD did not differ between bouts. CONCLUSION Well-trained games players experienced EIMD after exposure to both exercise tests, despite being accustomed to the exercise type. This suggests that well-trained athletes receive a very limited protective effect from the first bout.

Effects of seated and standing cold water immersion on recovery from repeated sprinting

Abstract This study investigated the effects of two different hydrostatic pressures (seated or standing) during cold water immersion at attenuating the deleterious effects of strenuous exercise on indices of damage and recovery. Twenty four male well-trained games players (age 23 ± 3 years; body mass 81.4 ± 8.7 kg: O2max 57.5 ± 4.9 ml∙kg−1∙min−1) completed the Loughborough Intermittent Shuttle Test (LIST) and were randomly assigned to either a control, seated cold water immersion or a standing cold water immersion (14 min at 14°C). Maximal isometric voluntary contraction, counter-movement jump, creatine kinase, C-reactive protein, interleukin-6 and delayed onset muscle soreness (DOMS) were measured before and up to 72 h following the LIST. All dependent variables showed main effects for time (P < 0.05) following the LIST, indicating physiological stress and muscle damage following the exercise. There were no significant group differences between control and either of the cold water immersion interventions. Seated cold water immersion was associated with lower DOMS than standing cold water immersion (effect size = 1.86; P = 0.001). These data suggest that increasing hydrostatic pressure by standing in cold water does not provide an additional recovery benefit over seated cold water immersion, and that both seated and standing immersions have no benefit in promoting recovery following intermittent sprint exercise.

Relation between Peak Power Output in Sprint Cycling and Maximum Voluntary Isometric Torque Production

From a cycling paradigm, little has been done to understand the relationships between maximal isometric strength of different single joint lower body muscle groups and their relation with, and ability to predict PPO and how they compare to an isometric cycling specific task. The aim of this study was to establish relationships between maximal voluntary torque production from isometric single-joint and cycling specific tasks and assess their ability to predict PPO. Twenty male trained cyclists participated in this study. Peak torque was measured by performing maximum voluntary contractions (MVC) of knee extensors, knee flexors, dorsi flexors and hip extensors whilst instrumented cranks measured isometric peak torque from MVC when participants were in their cycling specific position (ISOCYC). A stepwise regression showed that peak torque of the knee extensors was the only significant predictor of PPO when using SJD and accounted for 47% of the variance. However, when compared to ISOCYC, the only significant predictor of PPO was ISOCYC, which accounted for 77% of the variance. This suggests that peak torque of the knee extensors was the best single-joint predictor of PPO in sprint cycling. Furthermore, a stronger prediction can be made from a task specific isometric task.