ABSTRACT
The purpose of this study was to assess the status of nutrients intake in male Japanese collegiate athletes. Each 20 of baseball (B), soccer (S), volley ball (V), and long distance (L) athletes participated in this study. The B, S, and V athletes lived by themselves, whereas the L athletes lived in an athletes dormitory with provided meal. The nutritional status was assessed for 2 days. Mean energy intakes in the B, S, V, and L groups were 43.6, 53.7, 47.0, and 55.0 kcal/kg body weight, respectively. Mean protein intakes were 1.2, 1.6, 1.3 and 2.4 g/kg, respectively. In B athletes, skipping of breakfast was recognized frequently. Most of micronutrients intakes in the B, S, and V groups were less than the recommended dietary allowances for athletes. We suggest that a provided meal system is a better system for collegiate athletes and more nutritional education is necessary for Japanese male collegiate athletes, in particular, those living by themselves.
ABSTRACT
To determine the zinc (Zn) status in long distance runners during the period after the running season, Zn balance was measured in 12 male student long distance runners for five days. Daily dietary intake of energy and Zn were 3000 kcal and 38 mg, respectively. Twenty-four-hour urine Zn excretion exceeded the standard value, the serum Zn concentration was within the normal range, and the sweat Zn concentration was relatively low, but prominently positive Zn balances were observed 11 of the 12 subjects. These results suggest that the Zn status in long distance runners during runnning season is low or deficient.
ABSTRACT
It had been proposed by Kurata that relative threshold value F<SUB>th</SUB> of single motor units depends on the gradient G (kg/sec) of the tension increase of muscle in such a manner as<BR>F<SUB>th</SUB> (≡T.G) =ρG<SUP>λ</SUP><BR>Here T<SUB>1</SUB> is the time interval from the onset of EMG to the moment of recruitment of a motor unit and ρ is a proportional constant. The motor unit with a <I>positive/negative</I> value of λ is characterized to be <I>static/phasic</I>.<BR>Morimoto and Hasegawa reported that the above relation also holds for the relaxation period, provided that Ftn and G are replaced by the tension at the moment of silence and the absolute value of G, respectively. In this case, the motor unit with a <I>positive/ negative</I> value of λ is characterized to be <I>phasic/static</I>.<BR>In order to investigate the characteristics of motor units during relaxation period under the influence of pre-relaxation states, such as the increase of tension up to 4kg at the gradient of 0.5kg/sec and the state sustained at 4.0kg for 30sec. Single motor units of <I>m, vastus medialis</I> were studied by the same method as that of Morimoto and Hasegawa.<BR>The following results were obtained;<BR>1) Both at contraction and relaxation periods, the above relation was confirmed.<BR>2) The motor unit with characteristics of recruitment modes was influenced by the pre-relaxation state, but its tendency was not definite. These results suggest that <I>phasic/static</I> characteristics of motor units are not stationary but fluctuate depending on the pre-relaxation states.