Effect of endurance training on performance and muscle reoxygenation rate during repeated-sprint running

Abstract

The aim of the present study was to examine the effect of an 8-week endurance training program on repeated-sprint (RS) performance and post-sprints muscle reoxygenation rate in 18 moderately trained males (34 ± 5 years). Maximal aerobic speed (MAS), 10 km running and RS (2 × 15-s shuttle-sprints, interspersed with 15 s of passive recovery) performance were assessed before and after the training intervention. Total distance covered (TD) and the percentage of distance decrement (%Dec) were calculated for RS. Between-sprints muscle reoxygenation rate (Reoxy rate) was assessed with near-infrared spectroscopy during RS before and after training. After training, MAS (+9.8 ± 5.8%, with 100% chances to observe a substantial improvement), 10 km time (-6.2 ± 5.3%, 99%), TD (+9.6 ± 7.7%, 98%), %Dec (-25.6 ± 73.6%, 93%) and Reoxy rate (+152.4 ± 308.1%, 95%) were improved. The improvement of Reoxy rate was largely correlated with improvements in MAS [r = 0.63 (90% CL, 0.31;-0.82)] and %Dec [r = -0.52 (-0.15;-0.76)]. Present findings confirm the beneficial effect of endurance training on post-sprint muscle reoxygenation rate, which is likely to participate in the improvement of repeated-sprint ability after training. These data also confirm the importance of aerobic conditioning in sports, where repeating high-intensity/maximal efforts within a short time-period are required.

Recent developments in near-infrared spectroscopy (NIRS) for the assessment of local skeletal muscle microvascular function and capacity to utilise oxygen

“…The effects of training and de-training on the recovery time constant of muscle $\dot{\mathrm{V}}{\text{O}}_2$ measured by NIRS have also been shown in wrist flexor muscles 63 . Re-oxygenation rate following exercise is faster in trained individuals than in non-trained controls 28 and re-oxygenation rate can be improved by undertaking a training intervention 64 . Re-oxygenation is slower in patients with diseases affecting O 2 delivery, such as heart failure 65 but recently, exercise training has been shown to improve this reduction 45 …”

Is leg compression beneficial for alpine skiers?

“…Alterations in tissue concentrations of oxy- [HbO 2 ], deoxy- [HHb] and total hemoglobin [tHb] were monitored with a portable near-infrared spectrophotometer (NIRS) (Portamon, Artinis Medical System, Zetten, the Netherlands) attached with a 10 x 10-cm adhesive patch across the widest girth of the left vastus lateralis muscle, as described previously [28]. The distance from the base of the patella along the vertical axis of the thigh to the center of this device was approximately 10 cm.…”

“…The tissue saturation index (TSI, expressed as % and calculated as [HbO 2 ]/([HbO 2 ] + [HHB]) x 100) provided an indicator of the equilibrium between oxygen supply and consumption. Previous findings have demonstrated that the TSI provides a more accurate indication of muscle oxygenation than [HHb] [28,30]. The absolute TSI values observed at 30 s, 60 s, 120 s and 180 s into each trial were used for statistical analysis and the increases in these values following 15 s, 30 s, 60 s, 120 s and 300 s of recovery were taken as indices of the rate of re-oxygenation [28,31].…”

Influence of averaging method on muscle deoxygenation interpretation during repeated‐sprint exercise

“…To analyze a NIRS signal, single values for each sprint and recovery are typically determined for each peak and nadir . A mean is calculated over a predetermined duration within the closing seconds of each sprint and recovery periods to smooth fluctuations in raw NIRS data during sprint exercise .…”

“…A mean is calculated over a predetermined duration within the closing seconds of each sprint and recovery periods to smooth fluctuations in raw NIRS data during sprint exercise . This method has been used on numerous occasions in acute settings, varying inspired O 2 fraction, active vs passive rest, after respiratory muscle warm‐up, and in response to training . However, a possible drawback is that the true, physiological peak and/or nadir [HHb] may not fall within the predefined analysis window.…”