Changes in transverse relaxation time of quadriceps femoris muscles after active recovery exercises with different intensities

Abstract

The purpose of this study was to examine the changes in the metabolic state of quadriceps femoris muscles using transverse relaxation time (T2), measured by muscle functional magnetic resonance (MR) imaging, after inactive or active recovery exercises with different intensities following high-intensity knee-extension exercise. Eight healthy men performed recovery sessions with four different conditions for 20 min after high-intensity knee-extension exercise on separate days. During the recovery session, the participants conducted a light cycle exercise for 20 min using a cycle (50%, 70% and 100% of the lactate threshold (LT), respectively: active recovery), and inactive recovery. The MR images of quadriceps femoris muscles were taken before the trial and after the recovery session every 30 min for 120 min. The percentage changes in T2 for the rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT were significantly lower than those in either inactive recovery or 100% LT. There were no significant differences in those for vastus lateralis and vastus intermedius muscles among the four trials. The percentage changes in T2 of rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in either inactive recovery or 100% LT. Those of vastus lateralis and vastus intermedius muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in 100% LT. Although the changes in T2 after active recovery exercises were not uniform in exercised muscles, the results of this study suggest that active recovery exercise with the intensities below LT are more effective to recover the metabolic state of quadriceps femoris muscles after intense exercise than with either intensity at LT or inactive recovery.

Localization of damage in the human leg muscles induced by downhill running

“…More specifically, transverse relaxation time (T 2 )-weighted MRI can provide information on water content of muscle tissue given as a T 2 value, which can be then used as an index of the inflammatory edema induced by eccentric exercise 30, 31 . It has been reported that T 2 increases immediately post-exercise regardless of muscle damage 31–35 and subsides within as early as few minutes 36, 37 , and it increases again ≥~12 h post-exercise if muscle is damaged 36, 37 . For example, Ochi et al .…”

“…36 reported that T 2 significantly increased immediately post-exercise in the elbow flexors of both arms that performed either maximal concentric or eccentric contractions (5 sets × 6 reps), but T 2 returned to baseline at 1 day post-exercise in the concentrically exercised arm (without DOMS) while it remained elevated at 1, 3, and 5 days post-exercise in the eccentrically exercised arm (with DOMS). Thus, it is considered that the acute T 2 increase is associated with muscle activation during exercise 31–35 , and the delayed T 2 increase is a consequence of muscle damage (inflammatory edema), the degree of which is often greater than the acute one 31, 32, 37 . To support the usefulness of T 2 as an index of muscle damage, high correlation ( r  > 0.9) has been reported between changes in T 2 and plasma CK activity measured within several days after eccentric exercises 30, 38 .…”

Efficiency Variation in Cycling Exercise Related to Cadence and Work Rate Standardized by Ventilatory Threshold

“…Therefore the results could be applicable to the individuals who are diverse inˆber types, and would suggest that the higher e‹ciency at the higher work rate is derived with the magnitude of rate coding in Type Iˆbers. The eŠect of active recovery has been evaluated with light to moderate exercise intensity standardized by VT (Koizumi, K., et al (2011)) or LT (Mukaimoto, T., et al (2014)), and showed lower blood lactate concentration with the active condition. Mukaimoto, T., et al (2014) also compared 50z, 70z and 100zLT and showed the lower the intensity, the lower the lactate concentration.…”

“…The eŠect of active recovery has been evaluated with light to moderate exercise intensity standardized by VT (Koizumi, K., et al (2011)) or LT (Mukaimoto, T., et al (2014)), and showed lower blood lactate concentration with the active condition. Mukaimoto, T., et al (2014) also compared 50z, 70z and 100zLT and showed the lower the intensity, the lower the lactate concentration. In the present study, WE showed sig-niˆcantly lower value in 50zVT compared to the higher intensities of 75z and 100zVT.…”

“…It seems only by making use of the qualiˆed criteria which should set oŠ the multiplicity of the individual ability, the e‹ciency in the long-term exercise can be actually evaluated. Additionally, the long-term moderate exercise standardized by VT or lactate threshold (LT) has been used as a positive treatment after an intensive exercise bout (Active recovery; Fujita et al (2009), Mukaimoto et al (2014). Koizumi et al (2011) indicated the improved performance after the recovery exercise at 40zVT, concomitant with the decrease in blood lactate concentration and increased muscle oxygenation level.…”