1.Effect of muscle contraction type and speed on tissue oxygen dynamics in the M. vastus medialis during repeated knee extension exercise.
KAZUYA YASHIRO ; TAKAKO SAKAMOTO ; TOMOHO ISHII ; KAZUHIRO SUZUKAWA ; HIROSHI KIYOTA ; MAKOTO YAMATO ; SHOICHI NAKANO
Japanese Journal of Physical Fitness and Sports Medicine 2001;50(5):625-632
The purpose of this study was to analyze the relationship between activity pattern and temporal changes in the oxygen dynamics of human femoral medial vastus muscles. Oxygen dynamics were evaluated from the surface of the body by near-infrared spectroscopy (NIRS) . Arterial occlusion tests were performed in the femoral region at a cuff pressure of 300 mmHg. Exercise type and speed were controlled by CYBEX 6000. The exercise types examined were concentric contraction (CON) and eccentric contraction (ECC) . The 3 angular velocities of 90, 120 and 180 degrees were used as the exercise speeds. Exercise was performed continuously 60 times at maximum effort. The subjects were 7 healthy males with a mean age of 19.6±0.5 years. A transient decrease in oxygen concentration was observed during circulatory occlusion ; and rapid hyperemia occurred immediately after the removal of pressure. Oxygen concentration peaked above the control level and then returned to the initial level. In the CON exercise, the initial decrease in oxygen concentration was the largest at CON 90, and a gradual increase in oxygen concentration was clearly observed during exercise. In the recovery stage, after exercise at CON 90, 120 and 180, oxygen concentration exceeded the control level before exercise, then peaked and returned to the initial level. In the ECC exercise, an initial decrease in oxygen concentration was similar to that in the CON exercise, but a gradual increase in oxygen concentration was not observed during the exercise ; nor did oxygen concentration exceed the control level in the recovery stage after the exercise.
These results indicate that an increase in oxygen level after the removal of arterial occlusion, during and after the CON exercise was much higher than the control level before the exercise, sug-gesting the involvement of reactive hyperemia and exercise hyperemia.
2.Association between various levels of training-related energy expenditure and dietary and nutrient intake in Japanese male collegiate rugby players
Takako NISHIMURA ; Hideaki KUMAHARA ; Arisa GOTO ; Sayaka NISHIJIMA ; Momoko YOSHIYAMA ; Jun MURAKAMI ; Takako YAMATO
Japanese Journal of Physical Fitness and Sports Medicine 2019;68(1):71-82
This study aimed to explore the association between various levels of training-energy expenditure (TrEE) and nutritional response during the phases of periodization among male collegiate rugby players. Seventeen Japanese male collegiate rugby players were enrolled in the study. Their TrEE and dietary intake were assessed each day during three separate microcycle training phases in the preparatory phase of periodization (P1 and P2: general training phase consisting of two sessions per day over the term during which the school held classes and during a summer vacation, respectively; and P3: intensive training phase consisting of four sessions per day during a summer vacation) using the factorial method and dietary records, respectively. The TrEE for P3 (1644±273 kcal) was significantly higher than that for P1 (891±230 kcal). However, the total energy intake (EI) for P3 (3274±889 kcal) was significantly lower than that for P1 (3978±938 kcal). The daytime (after waking in the morning and before the evening training session) EI (242±159 kcal) and protein intake (19±12 g) from the ‘high-protein foods group’ during P3 was significantly reduced compared with that during P1 (465±252 kcal, 37±15 g), whereas, EI and carbohydrate intake from the ‘supplements group’ of P3 was significantly increased compared with P1. The increased TrEE during P3 was not compensated by EI; instead, there was a decreased nutrient intake from the high-protein foods group and increased intake from the supplements group. The time of day of multiple or intensive training sessions, i.e. different TrEE, might affect the food choices made by male rugby players.