The purpose of this study was to investigate the effects of environmental temperature conditions and running duration on the mechanical property changes of shoes having ethylene vinyl acetate (EVA) midsoles. Midsole temperature changes were obtained for a series of 40-min runs (2 subjects, 7 runs) under various seasonal environmental temperature conditions (winter 5–15 °C, summer 45–55 °C) for a normal shoe (35 durometers, Shore A). Midsole temperatures increased an average of 8 °C during the initial 15–20 min of running and were followed by relatively constant temperatures. Subsequently, the mechanical properties of soft (25 durometers), moderate (35 durometers), and firm (41 durometers) midsole shoes were evaluated using an impact tester over similar temperature ranges. With increasing temperature, peak deceleration and energy absorption decreased, and the times to peak deceleration and peak deformation increased. The results suggest that ordinary running shoes with moderate midsole hardness probably provide inadequate cushioning in cold environments and inadequate rearfoot control in hot environments.
Hiroshi Kinoshita and Barry T. Bates
Tomoko Aoki, Hayato Tsuda and Hiroshi Kinoshita
The purpose of this study was to examine finger motor function in terms of temporal and force characteristics during rapid single-finger tapping in older adults. Ten older and 10 young males performed maximum frequency tapping by the index, middle, ring, or little finger. Nontapping fingers were maintained in contact with designated keys during tasks. Key-contact force for each of the fingers was monitored using four force transducers. The older subjects had slower tapping rates of all fingers during single-finger tapping than the young subjects. The average forces exerted by the nontapping fingers were larger for the older subjects than for the young subjects during tapping with the ring and little fingers. The ranges of the nontapping finger forces were larger for the older subjects during tapping by the middle, ring, and little fingers than for the young subjects. Thus, the motor abilities of the fingers evaluated by rapid single-finger tapping decline in older adults compared with young adults in terms of both movement speed and finger independence.
Tomoko Aoki, Shinichi Furuya and Hiroshi Kinoshita
Using fast tapping tasks with each of the four fingers (single-finger tapping) and with two of the fingers used alternately (double-finger tapping), the ability to make rapid tapping movement by the individual fingers was compared between expert pianists and nonmusician controls in both genders. Maximal pinch and grasp forces were also measured to assess strength of individual fingers and whole hand, respectively. Movement of the ring and little fingers was slower than that of the index and middle fingers in both the pianists and controls. The slowness of the ring and little fingers was, however, much less evident in the pianists than the controls in both tapping tasks. The pianists also had smaller intertap interval variability for the index and middle fingers. No pianist–control difference was found for the pinch and grasp forces. Piano training, therefore, effectively changed the ability to move individual fingers rapidly, but not their flexor strength. No gender difference was found in any of the tapping tasks though males had greater strength. Gender thus does not appear to be a factor differentiating the ability to move individual fingers rapidly.
Takeshi Hirano, Kazutoshi Kudo, Tatsuyuki Ohtsuki and Hiroshi Kinoshita
This study investigated activity of the embouchure-related orofacial muscles during pre- and postattack phases of sound production by 10 trained French-horn players. Surface electromyogram (EMG) from five selected facial muscles, and related facial skin kinematics were examined in relation to pitch and intensity of a tone produced. No difference in EMGs and facial kinematics between the two phases was found, indicating importance of appropriate formation of preattack embouchure. EMGs in all muscles during the postattack phase increased linearly with an increase in pitch, and they also increased with tone intensity without interacting with the pitch effect. Orofacial skin movement remained constant across all pitches and intensities except for lateral retraction of the lips during high-pitch tone production. Contraction of the orofacial muscles is fundamentally isometric by which tension on the lips and the cheeks is regulated for flexible sound parameter control.