American Journal of Sports Science and Medicine

We aimed to examine the effects of wrist taping at different pressure levels on isokinetic strength exertion of dorsal and palmar flexion. Nineteen healthy male university students were enrolled. The wrist-taping method involved winding a rigid tape around wrist joint thrice. A qualified athletic trainer adjusted taping pressures using a pressure measuring system, whose sensor was on the palmaris longus muscle tendon of the dominant wrist. Isokinetic dorsal and palmar flexion strength was measured by an isokinetic dynamometer system. Taping pressure [5, 30, 60, and 90 hPa and control (no tape)] and angular velocity [slow (60°/sec), moderate (180°/sec), and fast (300°/sec)] were considered independent variables. Peak torque (Nm) of isokinetic strength exertion was considered the dependent variable. Two-way repeated measures analysis of variance (taping pressure × angular velocity) was used to calculate the mean differences for peak torque conditions. A significant difference was found only in the main effect of angular velocity. Multiple comparison tests showed that the isokinetic strength exertion was largest in fast flexion in all taping pressure conditions for dorsal flexion, whereas it was largestin slow flexion in the control and 5-hPa conditions for palmar flexion. For palmar flexion, it was larger in slow flexion for <5-hPa taping pressure, but not for>30-hPa. The effects of taping pressure and flexion speed on isokinetic strength exertion may differ between dorsal and palmar flexion of the same wrist.

American Journal of Sports Science and Medicine. 2014, 2(6), 222-226. DOI: 10.12691/ajssm-2-6-4
Pub. Date: December 31, 2014

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Effect of Differences in the Exercise Frequency of Young People on Abdominal Strength and Muscle Thickness

by Takanori Noguchi and Shinichi Demura

Original Research

Differences in the frequency of exercise among individuals increase during adolescence. These individual differences are associated with developmental differences in abdominal muscle groups that are closely related to activities of daily living. We examined the effect of differences in exercise frequency in young people on abdominal strength and muscle thickness. The subjects were 20 young male university athletes who belonged to sports clubs and who exercised >6 days per week for >3 h per day (athlete group: age, 20.1 ± 1.43 years; height, 171.7 ± 6.74 cm; weight, 67.9 ± 10.41 kg) and 20 young university male students who did not habitually exercise (less than twice per week) (nonathlete group: age, 20.1 ± 1.41 years; height, 171.6 ± 5.46 cm; weight, 63.2 ± 8.62 kg). Their physical characteristics (height, weight, and body mass index), abdominal flexion strength, and abdominal muscle thickness (rectus abdominis, external oblique, internal oblique muscles) were measured. Although no significant differences were found in the physical characteristics of either group, abdominal strength and all muscle thickness were significantly greater in the athlete group than that in the nonathlete group. In addition, a relatively high correlation between abdominal strength and muscle thickness was found only in the athlete group (r = 0.73). In conclusion, abdominal strength and muscle thickness were greater in young athletes who frequently exercise compared with that in nonathletes. Abdominal muscle strength increased with increasing abdominal muscle thickness in the athletes but not in the nonathletes.

American Journal of Sports Science and Medicine. 2014, 2(6), 218-221. DOI: 10.12691/ajssm-2-6-3
Pub. Date: December 18, 2014

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Japanese Women’s Age-related Differences between Controlled Force Exertion Measured by a Computer-generated Sinusoidal Waveform and a Bar Chart Display

by Yoshinori Nagasawa and Shinichi Demura

Original Research

Because developing an accurate method of measuring controlled force exertion is important, this study examined age differences in corresponding relationships between controlled force exertions measured by sinusoidal waveform and bar chart displays. Additionally, the study clarified the judgment score of the controlled force exertion’s decrease. Participants were 215 right-handed female adults, aged 20–84, in three age groups: young (n = 64, mean age 24, SD = 2.8 years), middle-aged (n = 91, mean age 43, SD = 8.0 years), and elderly (n = 60, mean age 68, SD = 6.5 years). They matched the submaximal grip strength in their dominant hand to changing demand values displayed on a personal computer screen as either a sinusoidal waveform or a bar chart. They performed the tests three times with 1-minute inter-trial intervals. The dependent variable was the total of percentage values of differences between the demand and grip exertion values for 25 seconds. In both displays, the coefficient of variance had almost the same range in all age groups (CVSW = 25.9–32.0, CVBC = 21.2–38.8), but the elderly group showed a somewhat higher value with the bar chart. Three groups had significant correlations between scores with the sinusoidal waveform and bar chart displays (r = 0.33–0.64), but their values did not differ significantly among age groups. Only 0%–3% of the middle-aged group had scores over 1500%; 23%–33% of the elderly group did. Furthermore, only 15% of the elderly group had scores over 1500% in both displays. There is a moderate relationship between the controlled force exerted in response to the sinusoidal waveform and bar chart displays, and it does not show age differences. In controlled force exertion, scores over 1500% in both displays are considered inferior to scores under 1500%.

American Journal of Sports Science and Medicine. 2014, 2(6), 212-217. DOI: 10.12691/ajssm-2-6-2
Pub. Date: December 03, 2014

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Characteristics of Static and Dynamic Balance Abilities in Competitive Swimmers

by Hiroki Sugiura, Shinichi Demura, Tamotsu Kitabayashi, Yoshimitsu Shimoyama, Daisuke Sato, Ning Xu and Yuko Asakura

Original Research

Competitive swimmers may have inferior balance because antigravity strength exertion, which is used to stand, is not often necessary in the water. This study concerns the ability to stand with the manipulating and supporting legs and their laterality by examining 16 male competitive swimmers (age: 19.4±1.0 years, career: 13.7±2.1 years) and 16 male general university students (age: 20.6±1.2 years). Static balance and dynamic balance were evaluated by the center sway of foot pressure and stability on an unstable stool, respectively. The total path length, mean path length, maximal amplitude rectangle, root mean square area, and outline area for the former and the fluctuation index for the latter were selected as evaluation parameters. The results of a two-way ANOVA (group × leg) showed no significant difference in both the group and leg factors for static balance parameters. In contrast, the dynamic balance parameter showed a significant difference in both. Stability on an unstable stool was higher in the swimmer group than in the general student group and in the manipulating leg than in the supporting leg in both groups. In conclusion, dynamic balance while standing with the manipulating or supporting leg is superior in competitive swimmers, unlike static balance assessed by the center sway of foot pressure. In addition, dynamic balance in the manipulating leg is superior to that in the supporting leg for both groups.

American Journal of Sports Science and Medicine. 2014, 2(6), 208-211. DOI: 10.12691/ajssm-2-6-1
Pub. Date: November 18, 2014

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