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Purpose: This cross-sectional study aimed to investigate the ability to adjust grip strength by comparing the characteristics of force generation and relaxation from childhood to adulthood. Method: This study included 225 participants aged 6, 11, 17, and 19-23 years (adults) who performed isometric hand-grip force as follows: maximum, half generation, and half relaxation. The force was recorded, and relative values and errors were calculated for half tasks. Results: The maximum task values increased with age, but there was no significant age difference between 17-year-olds and adults. The difference between sexes was significant; males were stronger than females in both 17-year-olds and adults. Both sexes in all age groups had greater errors in half relaxation than in half generation tasks. Females had negatively greater constant error than males in half tasks. The errors of 6-year-olds were greater than the other age groups in half tasks. Conclusion: There is a developmental trend for producing maximal strength that is similar across sexes until adolescence when males are stronger and females plateau. The ability of force relaxation was more difficult to accurately control than force generation for all age groups and was adult-like by middle childhood.

Purpose: The purpose of this study was to investigate the effects of tongue-strengthening exercise (TSE) on tongue strength and effortful swallowing pressure in young healthy adults. Method: Thirteen young healthy volunteers (six men, seven women; M[subscript age] = 20.5 ± 0.5 years) performed 8 weeks of isometric TSE 3 days per week. A tongue pressure measurement device was used to measure maximum isometric tongue pressure (MITP) and conduct the TSE, and a tactile sensor system attached to the hard palate was used to measure effortful swallowing pressure. MITP and effortful swallowing pressure were measured at baseline, after 4 and 8 weeks of training, and at 4 and 8 weeks after the last training session to examine the detraining effects. Results: The results indicated that both MITP and effortful swallowing pressure increased significantly from baseline to 8 weeks after training. Although the improved MITP significantly decreased at 4 and 8 weeks after training cessation, no detraining effect was observed for effortful swallowing pressure. Conclusions: TSE is an effective method for increasing tongue pressure in wide tongue-palate contact areas during effortful swallow. The effortful swallowing pressure gained with TSE appears to be maintained for at least eight nontraining weeks.

This study examined the characteristics, such as muscle power and agility, of top-level junior soft tennis players. 36 Japanese top-level junior (under-14) boys soft tennis players (age 13.4 ± 0.8 years, height 165.0 ± 9.7cm, and weight 53.9 ± 11.1 kg) with experience in international meet participation and 25 junior boys soft tennis players (age 13.1 ± 0.7 years, height 158.2 ± 9.5cm, weight 47.0 ± 8.2 kg) with experience in prefectural meet participation were the subjects of this study. Medicine ball (2 kg) throws to the right or left by trunk rotation and forward and backward by trunk extension (exercises recommended by Japan's soft tennis association) were selected to evaluate the muscle power of the subjects. Side step, spider, and front-back shuttle run tests (used by an American tennis association) were selected to test the agility of the subjects. The top-level athletes were significantly superior to the other junior players in the forward medicine ball throw, side step, and spider tests. These results suggest that muscle power in the forward direction and agility when moving to the right, left or diagonal direction are more developed in top-level soft tennis players than in other players.

Purpose: The aim of this study was to investigate a structured approach for effective speech therapy (ST) for dysarthria and speech-related quality of life in patients with sporadic spinocerebellar degeneration (SCD), including cerebellar-type multiple-system atrophy and cerebellar cortical atrophy. Method: Twenty-two patients with SCD (cerebellar-type multiple system atrophy, 15 patients; cerebellar cortical atrophy, seven patients) who underwent intensive ST were examined. Dysarthria was evaluated using the Scale for Assessment and Rating of Ataxia Speech Dysfunction, Assessment of Motor Speech for Dysarthria Articulation, oral diadochokinesis (OD), and Voice Handicap Index-10 (VHI-10). Respiratory muscle strength (inspiratory and expiratory pressure) and respiratory-phonatory coordination (maximum phonation time) were measured. Cognitive function was evaluated using the Montréal Cognitive Assessment and the word fluency test. Mood was evaluated using the Hospital Anxiety and Depression Scale. The relationships between dysarthria scales (particularly, VHI-10) and clinical data were analyzed using stepwise regression. The differences in outcomes after intensive ST were analyzed using the Wilcoxon signed-rank test. The alpha level (p) for statistical significance was set at 0.0125 by Bonferroni correction. Results: For both pre- and post-ST, the patient's OD (p = 0.002) and maximum phonation time (p = 0.002) significantly improved, except for Speech Dysfunction scores of the Scale for Assessment and Rating of Ataxia (p = 0.705) and the VHI-10 (p = 0.018). The Assessment of Motor Speech for Dysarthria Articulation, OD, and inspiratory pressure were identified as independent variables of VHI-10 (adjusted R[subscript 2] = 0.820) for speech-related quality of life; no correlations among the Montréal Cognitive Assessment, word fluency test, and Hospital Anxiety and Depression Scale scores were observed. Conclusion: OD and VHI-10 showed improvements due to changes in speech function and respiratory-phonatory coordination, justifying intensive ST treatment for dysarthria in patients with SCD.

Physical fitness is one of the key factors in healthy aging. Although physical fitness is widely recognized to decline with age, age-related decreases in the individual dimensions of physical fitness in later life are less clear. Purpose: The purpose of the present study was to describe the age-related changes in six fitness components covering a variety of motor dimensions in men and women through a 12-year longitudinal epidemiological study. Method: Participants were randomly selected community-living men (n = 1,139) and women (n = 1,128) aged 40 to 79 years at baseline who were repeatedly tested over a mean (standard deviation) follow-up period of 9.8 (3.4) years with a mean of 4.9 (2.3) examinations. The six physical fitness tests were sit-and-reach, grip strength, sit-ups, one-leg standing, reaction time and leg extension power. The effect of age on each physical fitness task was analyzed using a mixed-effects model controlling for habitual physical activity level. Results: The fixed effect of the interaction of age and time in all fitness tests was significant in men. Higher age at baseline was significantly associated with a greater decrease over time except in one-leg standing. In women, no significant interaction effect of age and time was found in grip strength or reaction time. Age-related changes in grip strength and reaction time were constant with increasing age. Conclusion: Twelve-year longitudinal data showed that the age-related decrease in physical fitness over time, especially musculoskeletal fitness in men, was pronounced, whereas in women, the decrease was less pronounced.

The aim of this study was to clarify the intra- and inter-rater reliability of the rate of force development in hip abductor muscle force measurements using a hand-held dynamometer. Thirty healthy adults were separately assessed by two independent raters on two separate days. Rate of force development was calculated from the slope of the force-time curve that was divided into four time intervals (50, 100, 200, and 300 ms). The highest values of the three trials were used for statistical analysis. The intra-class correlation coefficient with a 95% confidence interval, standard error of measurement, and minimal detectable change at the 95% confidence level were calculated for each interval. For assessment of systematic error, Bland-Altman analysis was used. The results indicated that intra- and inter-rater reliability of the highest values at all intervals were sufficient (intra-class correlation coefficient > 0.7). The Bland-Altman analysis did not show systematic error in either reliability measure.

This study examined age group and individual differences in controlled force exertion by emulating sinusoidal and quasi-random waveforms in 222 right-handed female adults aged 20 to 86 years. The subjects matched their submaximal grip strength by the dominant hand to changing demand values displayed as either a sinusoidal or a quasi-random waveform appearing on the display of a personal computer. A total of the differences between the demanded value and grip exertion value for 25 seconds was used as an evaluation parameter. The measurements showed a tendency to increase across the age groups in both waveforms. Significant second-order curve regressions were identified, but there was no significant difference in the increase rates of both waveforms. Analysis of variance showed non-significant differences among means of both waveforms in all age groups, and the differences between means in groups of participants over 50 and 20- to 24-year-olds increased in both waveforms. Individual differences were almost the same in both waveforms. (Contains 2 tables and 3 figures.)

BACKGROUND: Few studies have investigated the variations in body composition and performance in Japanese collegiate American-football players. OBJECTIVE: To clarify what characterizes competitors at the highest levels – in the top division or on the starting lineup – we compared players' body compositions and performance test results. METHODS: This study included 172 players. Each player's body composition and performance (one-repetition maximum bench press, one-repetition maximum back squat, and vertical jump height) were measured; power was estimated from vertical jump height and body weight. Players were compared according to status (starter vs. non-starter), position (skill vs. linemen), and division (1 vs. 2). Regression analysis was performed to determine characteristics for being a starter. RESULTS: Players in higher divisions and who were starters were stronger and had more power, greater body size, and better performance test results. Players in skill positions were relatively stronger than those in linemen positions. Vertical jump height was a significant predictor of being a starter in Division 1. CONCLUSION: Power and vertical jump may be a deciding factor for playing as a starter or in a higher division. [ABSTRACT FROM AUTHOR]

PURPOSE: This study aimed to investigate the effects of wearing a compression garment (CG) for 24 h on changes in muscular strength and blood parameters over time after resistance exercise. METHODS: Nine trained men conducted resistance exercises (10 repetitions of 3-5 sets at 70% of one-repetition maximum (1RM) for nine exercises) in two trials, wearing either a CG or a normal garment (CON) for 24 h after exercise. Recovery of muscular strength, blood parameters, muscle soreness, and upper arm and thigh circumference were compared between the trials. RESULTS: Both trials showed decreases in maximal strength after the exercise (P < 0.05). However, the CG trial showed faster recovery of one-repetition maximum for the chest press from 3 to 8 h after exercise (P < 0.05). Recovery of maximal knee extension strength was also improved in the CG trial 24 h after exercise (P < 0.05). The CG trial was associated with lower muscle soreness and subjective fatigue scores the following morning (P < 0.05). The upper arm and thigh circumferences were significantly higher during the recovery period in the CON trial, whereas no change was observed in the CG trial. Blood lactate, insulin like growth factor-1, free testosterone, myoglobin, creatine kinase, interleukin 6, and interleukin 1 receptor antagonist concentrations for 24 h after exercise were similar in both trials. CONCLUSIONS: Wearing a CG after resistance exercise facilitates the recovery of muscular strength. Recovery for upper body muscles significantly improved within 3-8 h after exercise. However, facilitation of recovery of lower limb muscles by wearing the CG took a longer time. [ABSTRACT FROM AUTHOR]

Background. Adequate levels of physical balance and muscular strength are necessary to live independently in old age. The effects of an exercise training program targeting the sensory and muscle systems on balance and strength in a group of older adults were determined in this study.Methods. Static balance (one-leg balance with eyes closed), dynamic balance (limits of stability {endpoint excursion [EPE], maximum excursion [MXE]}), and strength (chair stand) were assessed before and after the intervention. Volunteers were divided randomly into a training group (TR, n = 15, 76 ± 4 years) and a control group (CN, n = 14, 76 ± 7 years). TR performed 12-week (2 days/week, 60 min/day) supervised training while standing on the floor (first 4 weeks) and progressing to standing on foam pads of different compliances. Exercises included movements that challenged the sensory and muscle systems.Results. After 12 weeks of training, the TR demonstrated significant improvements in static balance (82%); EPE backward (72%), right (32%), and left (33%); MXE backward (74%), right (31%), and left (18%); and lower body muscle strength (20%) with no significant changes in CN.Conclusion. These results indicate that this training program is very effective in improving balance and lower body strength in older adults. [Copyright &y& Elsevier]

Male sexual function is regulated by vascular function and impaired vascular function is closely related with erectile dysfunction (ED). Vascular functions are positively influenced by physical fitness (i.e., aerobic capacity, muscle strength, and flexibility). The detailed associations between physical fitness and male sexual function remain poorly understood. The present study aimed to clarify the influence of physical fitness on male sexual function. In 177 adult men, peak oxygen consumption (VO 2 peak ), handgrip strength (HGS), and sit and reach were measured as indices of physical fitness. Arterial stiffness and erectile function were assessed by carotid-femoral pulse wave velocity (cfPWV) and the International Index of Erectile Function 5 (IIEF5) questionnaire, respectively. IIEF5 score was significantly correlated with VO 2 peak ( r s = 0.52), HGS ( r s = 0.37), and cfPWV ( r s = -0.44); and multivariate linear regression analyses showed that VO 2 peak , HGS, and cfPWV were significantly associated with IIEF5 score after considering confounders. The receiver operator characteristic curve analysis suggested that the cutoff values for predicting ED were 29.0 ml/min/kg for VO 2 peak and 39.3 kg for HGS. The IIEF5 score was the highest in the subjects with the values of both VO 2 peak and HGS were higher than their respective cutoff values, while the IIEF5 score was the lowest in the subjects with the values of both VO 2 peak and HGS were lower than their respective cutoff values. These results suggest that the maintenance of high aerobic capacity and muscular strength may offset deterioration of male sexual function.