Wearable lactate threshold predicting device is valid and reliable in runners

Wearable lactate threshold predicting device is valid and reliable in runners. J Strength Cond Res 30(8): 2212-2218, 2016 - A commercially available device claiming to be the world's first wearable lactate threshold predicting device (WLT), using near-infrared LED technology, has entered the market. The aim of this study was to determine the levels of agreement between the WLT-derived lactate threshold workload and traditional methods of lactate threshold (LT) calculation and the interdevice and intradevice reliability of the WLT. Fourteen (7 male, 7 female; mean ± SD; age: 18-45 years, height: 169 ± 9 cm, mass: 67 ± 13 kg, Vo 2 max: 53 ± 9 ml·kg -1 ·min -1) subjects ranging from recreationally active to highly trained athletes completed an incremental exercise test to exhaustion on a treadmill. Blood lactate samples were taken at the end of each 3-minute stage during the test to determine lactate threshold using 5 traditional methods from blood lactate analysis which were then compared against the WLT predicted value. In a subset of the population (n 12), repeat trials were performed to determine both inter-reliability and intrareliability of the WLT device. Intraclass correlation coefficient (ICC) found high to very high agreement between the WLT and traditional methods (ICC > 0.80), with TEMs and mean differences ranging between 3.9-10.2% and 1.3-9.4%. Both interdevice and intradevice reliability resulted in highly reproducible and comparable results (CV 0.97). This study suggests that the WLT is a practical, reliable, and noninvasive tool for use in predicting LT in runners. © 2015 National Strength and Conditioning Association.Borges, NR and Driller, MW

Individualized sleep education improves subjective and objective sleep indices in elite cricket athletes: A pilot study

The aim of the current study was to evaluate the effect of personalized sleep hygiene education on sleep indices in elite athletes. Nine elite male cricket players performed 3 weeks of baseline sleep monitoring (PRE), followed by group and individualized sleep hygiene education and a further 3 weeks of sleep monitoring (POST). Subjective sleep questionnaires included the Athlete Sleep Behaviour Questionnaire (ASBQ), the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). Objective sleep indices were monitored via wrist actigraphy. There were significant improvements (p < 0.05) in two of the sleep questionnaires (ESS and PSQI) and in sleep efficiency (+5%), sleep latency (−29 min) and sleep onset variance (−28 min) following the intervention, all associated with large or very large effect sizes (d= 1.38, −0.85 and −0.88, respectively). The current study reports that personalized sleep hygiene education using the ASBQ to target maladaptive sleep behaviours may be effective in acutely improving sleep indices in elite male athletes. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group

Age-related changes in physical and perceptual markers of recovery following high-intensity interval cycle exercise

Background: The purpose of this study was to compare physical performance, perceptual and haematological markers of recovery in well-trained masters and young cyclists across 48 h following a bout of repeated high-intensity interval exercise. Methods: Nine masters (mean ± SD; age = 55.6 ± 5.0 years) and eight young (age = 25.9 ± 3.0 years) cyclists performed a high-intensity interval exercise session consisting of 6 × 30 s intervals at 175% peak power output with 4.5 min rest between efforts. Maximal voluntary contraction (MVC), 10 s sprint (10SST), 30-min time trial (30TT) performance, creatine kinase concentration (CK) and perceptual measures of motivation, total recovery, fatigue and muscle soreness were collected at baseline and at standardised time points across the 48 h recovery period. Results: No significant group-time interactions were observed for performance of MVC, 10SST, 30TT and CK (P > 0.05). A significant reduction in 10SST peak power was found in both masters (P = 0.002) and young (P = 0.003) cyclists at 1 h post exercise, however, both groups physically recovered at similar rates. Neither group showed significant (P > 0.05) or practically meaningful increases in CK (%∆ < 10%). A significant age-related difference was found for perceptual fatigue (P = 0.01) and analysis of effect size (ES) showed that perceptual recovery was delayed with masters cyclists reporting lower motivation (ES ±90%CI = 0.69 ± 0.77, moderate), greater fatigue (ES = 0.75 ± 0.93, moderate) and muscle soreness (ES = 0.61 ± 0.70, moderate) after 48 h of recovery. Conclusion: The delay in perceived recovery may have negative effects on long-term participation to systematic training. © 2018, © 2018 Taylor & Francis Group, LLC

Autonomic cardiovascular modulation in masters and young cyclists following high-intensity interval training

© 2017, Springer-Verlag Berlin Heidelberg. Purpose: This study aimed at examining the autonomic cardiovascular modulation in well-trained masters and young cyclists following high-intensity interval training (HIT). Methods: Nine masters (age 55.6 ± 5.0 years) and eight young cyclists (age 25.9 ± 3.0 years) completed a HIT protocol of 6 x 30 sec at 175% of peak power output, with 4.5-min’ rest between efforts. Immediately following HIT, heart rate and R–R intervals were monitored for 30-min during passive supine recovery. Autonomic modulation was examined by i) heart rate recovery in the first 60-sec of recovery (HRR 60 ); ii) the time constant of the 30-min heart rate recovery curve (HRRτ); iii) the time course of the root mean square for successive 30-sec R–R interval (RMSSD 30 ); and iv) time and frequency domain analyses of subsequent 5-min R–R interval segments. Results: No significant between-group differences were observed for HRR 60 (P = 0.096) or HRR τ (P = 0.617). However, a significant interaction effect was found for RMSSD 30 (P = 0.021), with the master cyclists showing higher RMSSD 30 values following HIT. Similar results were observed in the time and frequency domain analyses with significant interaction effects found for the natural logarithm of the RMSSD (P = 0.008), normalised low-frequency power (P = 0.016) and natural logarithm of high-frequency power (P = 0.012). Conclusion: Following high-intensity interval training, master cyclists demonstrated greater post-exercise parasympathetic reactivation compared to young cyclists, indicating that physical training at older ages has significant effects on autonomic function

Wearing compression socks during exercise aids subsequent performance

Objectives: To assess the effect of wearing compression socks on immediate and subsequent 5 km running time trials, with particular attention to the influences on physiological, perceptual and performance-based parameters. Design: Counter-balanced cross-over experiment. Methods: Twelve male runners (mean ± SD 5 km run time 19:29 ± 1:18 min:s) each completed two experimental sessions. Sessions consisted of a standardised running warm-up, followed by a 5 km time trial (TT1), a one hour recovery period, then a repeat of the warm-up and 5 km time trial (TT2). One session required the use of sports compression socks during the first warm-up and time trial (COMP), while the other did not (CON). Results: The decline in run performance in CON from TT1 to TT2 was moderate and significantly greater than that experienced by runners in COMP (9.6 s, d = 0.67, p < 0.01). No difference was found between experimental conditions for oxygen consumption, blood lactate or calf volume (p = 0.61, 0.54, 0.64, respectively). Perceptual measures of muscle soreness, fatigue and recovery were also similar between trials (p = 0.56, 1.00 & 0.61, respectively). Conclusions: Wearing sports compression socks during high intensity running has a positive impact on subsequent running performance. The underlying mechanism of such performance enhancement remains unclear, but may relate to improved oxygen delivery, reduced muscle oscillation, superior running mechanics and athlete beliefs