1.INFLUENCE OF DIFFERENT STRETCHING ON RANGE OF MOTION AND RUNNING ECONOMY IN LONG DISTANCE RUNNERS
TAIJI OHSHITA ; RYOUICHI MITSUZONO
Japanese Journal of Physical Fitness and Sports Medicine 2009;58(3):395-404
The purpose of this study was to examine the influence of autostretching and static stretching on range of motion (ROM) and running economy (RE) in long-distance runners. Twenty-two male distance runners were randomly assigned to an autostretching group (n=8), a static stretching group (n=7) and non-intervention control group (n=7). The experimental protocol was composed of interventions between treadmill runnings for RE. The interventions were either autostretching or static stretching, after the first treadmill running. The oxygen consumption (VO2) as RE was measured at three steady-state running speeds (240m/min, 268m/min, and 295m/min). Goniometric measurements of hip flexion and ankle dorsiflexion ROM were taken immediately before and after each treadmill running for RE. The results showed that the autostoretching group had a significant decrease in VO2 at 240m/min (p<0.05), and at 268m/min (p<0.05). On the other hand, the control group had a significant increase in VO2 only at 295m/min (p<0.05). At the same time, the autostretching group had significant improvements in ROM for hip flexion (p<0.05) and ankle dorsiflexion (p<0.05). The static stretching group had no significant changes in RE or ROM. The results of this experiment suggest that autostretching had a positive effect in improving RE in subjects of this study, and indicate the possibility that improved RE leads to the improvement of long-distance runners' performance.
3.Relationship between muscle fiber composition, capillary supply, oxidative enzyme activity and aerobic work capacity in middle- and long-distance runners.
RYOUICHI MITSUZONO ; SHIGERU KATSUTA ; YOUJI KANAO ; KEN-ICHI TABUCHI ; JUN NAGAI
Japanese Journal of Physical Fitness and Sports Medicine 1986;35(4):182-191
It was the purpose of this study to examine the property of skeletal muscle fiber in middle- and long-distance runners, and to evaluate the relationship between the property of skeletal muscle fiber and aerobic work capacity.
Biopsy samples were taken from M, vastus lateralis of 23 middle- and long-distance runners, and analyzed for muscle fiber composition, capillary supply and SDH activity. Aerobic work capacity was measured on a treadmill with continuous method.
The mean value for % ST in M. vastus lateralis was 61.3%, and the muscle fiber distribution showed the tendency of slow type. The crosssectional area of ST and FT fibers ranged approximately from 3, 000 μm2 to 13, 000 μm2, and the cross-sectional area of ST fiber tended to be larger than that of FT fiber. The mean values for CD, C/F ratio, and CC (/ST) as capillary supply were 279/mm2, 1.62 and 5.7, respectively. The mean value for SDH activity was 5.86 μmoles/g/min, and was lower than reported previously for elite runners. In addition, SDH activity correlated with % ST and CC (/ST) (r=0.480, p<0.05, r=0.640, p<0.01) . On the other hand, the mean value for VOG2max was 68.5 ml/ kg/min (4, 066 ml/min), while VO2@AT averaged 45.9 ml/kg/min (2, 756 ml/min) . And it was found that VO2max and VO2@AT correlated significantly with % ST, CC (/ST) and SDH activity. Particular, VO2 max was most strongly related to SDH activity (r=0.612, p<0.01) .
The results of this study suggest that in regard to middle- and long-distance runners, structural characteristics of the ST fiber and capillary are some of the indispensable factors to regulate such a functional property as SDH activity and that the distinctive characteristics of the skeletal muscle fiber might possibly influence aerobic work capacity to a great extent.