Changes in blood volume and oxygenation level in a working muscle during a crank cycle

Abstract

The results suggest that circulatory and metabolic conditions of a working muscle can be easily affected during pedaling exercise by work intensity. The present method, reordering of NIRS parameters against crank angle, serves as a useful measure in providing additional findings of circulatory dynamics and metabolic changes in a working muscle during pedaling exercise.

Effects on the crank torque profile when changing pedalling cadence in level ground and uphill road cycling

“…However, competitive cyclists generally climb hills at lower pedalling cadences (close to 70 rpm) ( Lucia et al, 2001) than when cycling in level ground conditions, despite several studies suggesting that using higher pedalling cadences could improve performance (Patterson and Moreno, 1990;Swain and Wilcox, 1992;McNaughton and Thomas, 1996;Neptune and Herzog, 1999;Marsh et al, 2000). Using higher pedalling cadences during uphill cycling could : (1) reduce the muscle mass used to stabilise the trunk, (2) reduce cycling velocity oscillations, (3) increase blood flow and oxygenation to working muscles (Swain and Wilcox, 1992;Takaishi et al, 2002) and (4) decrease the crank inertial load to reduce the stimulation of mechanoreceptors in the lower limbs (Hansen et al, 2002a,b). Moreover, higher pedalling cadences allow an important reduction of mean torque and T peak : For the same power output, the mean torque at 80 rpm is 25% lower compared with the mean torque at 60 rpm.…”

“…Using the most economical cadence does not always signify that the most optimal cadence is used. The decreased muscle stress (by increasing pedalling cadence) could contribute to a greater relative recruitment of ST muscle fibers which have greater fatigue resistance and a higher mechanical efficiency, despite increased oxygen consumption caused by increased repetitions of leg movements (Takaishi et al, 1998(Takaishi et al, , 2002. Also, Swain et al, 1992 have shown that uphill cycling was more economical at higher pedalling cadences.…”

Biceps brachii myoelectric and oxygenation changes during static and sinusoidal isometric exercises

“…A number of previous studies have combined sEMG data with muscle oxygenation data (by NIRS) during exercise (Burnley et al, 2002;Kouzaki et al, 2003;Miura et al, 2000;Praagman et al, 2003;Takaishi et al, 2002;Yoshitake et al, 2001). For example, Miura et al (2000) and Yoshitake et al (2001) reported a correlation between dynamic exercise intensity, increased neuromuscular activation and aerobic metabolism.…”

Resting mechanomyography before and after resistance exercise

“…It has been shown that muscle is ischemic during strong resistive contraction, and that aerobic exercise while cycling, by virtue of frequent repetitions of shorter durations produce brief, rapidly corrected periods of ischemia, or no ischemia at all. (Takaishi 2002;Osada 2004). The greater reactive hyperemia after resistance exercise would in turn increase engorgement of the exercised muscle with blood, increasing its intramuscular pressure in the immediate period following exercise, and decreasing compliance.…”