Jinzaburo Matsuzawa

Ability to coordinate exertion of force by the dominant hand: comparisons among university students and 65- to 78-year-old men and women.

The purposes of this study were to examine the characteristics of ability to coordinate exertion of force in 60 healthy older people (30 men, 30 women) from the viewpoint of sex differences and to compare their performance with those of 60 healthy university students (30 men, 30 women). The test of ability to coordinate exertion of force was conducted by having the subject fit the exertion value of grip strength to a changing demand value appearing on the display of a personal computer (using a bar chart-description form). The changes in the demand value were tracked. The variable estimating ability to coordinate exertion of force was the total sum of the differences between demand and the produced grip strength induced by time lapses. The ability to coordinate exertion of force in the older subjects was inferior to that of the younger subjects, and large individual differences were observed. Unlike the younger subjects, the means of the ability to coordinate exertion of force of the older subjects significantly decreased between trials. The ability to coordinate exertion of force of the older women was significantly inferior to that of the older men, but the means of the measurements among three trials shows a similar tendency to decrease in both sexes.

Agreement in Depression Determination among Four Self-Rating Depression Scales Applied to Japanese Community-Dwelling Elderly

ObjectiveIn this study, we examined the characteristics of depression determination using four representative self-rating depression scales (Geriatric Depression Scale, GDS; Self-rating Depression Scale, SDS; Center for Epidermiologic Studies Depression Scale, CES-D; and Carroll Rating Scale, CRS) applied to Japanese community-dwelling elderly.MethodsSubjects were 563 community-dwelling independent elderly living in twelve prefectures (330 males, 68,9±6.3 yr; 233 females, 68.1±5.8 yr).ResultsDepression rates determined using SDS (45.8%) and CES-D (68.6%) were higher than those determined using GDS (5.7%) and CRS (14.7%). Although correlations of depression scale scores among the four scales were significant and comparable (r: 0.61 (GDS vs. SDS, p<0.01) to 0.78 (SDS vs. CES-D, p<0.01)), the agreement in depression determination varied among scales (kappa coefficients: 0.05 (GDS vs. CES-D, p>0.05) to 0.46 (SDS vs. CES-D, p<0.01)).ConclusionsSimilarities in depression determination were found between GDS and CRS, and between CES-D and SDS. Depression rates determined on the basis of cut-off point for each scale were higher for CES-D and SDS than for GDS and CRS. Depression determination using a four-point rating scale may overestimate a slightly depressive symptom, compared with that using a two-point scale.

Comparison in the Effect of Linear Polarized Near-infrared Light Irradiation and Light Exercise on Shoulder Joint Flexibility

ObjectiveThis study aimed at comparing the effect of linear polarized near-infrared light irradiation (PL irradiation) and bicycle exercise with 50%HRreserve on the flexibility of the shoulder joint. DesignPlacebo-controlled trial. SettingTwenty-four healthy young adults (10 males: mean±SD, age 20.9±3.1 y, height 171.0±3.9 cm, body mass 63.4±3.5 kg and 14 females: age 21.2±1.7 y, height 162.0±7.8 cm, body mass 56.2±7.2 kg). InterventionsPL-irradiation (100%, 1800 mW), placebo-irradiation (10%,180 mW), and light exercise (50%HRreserve) for 10 minutes. Outcome Measurements and ResultsThe shoulder joint angles were measured twice-before and after each intervention. We measured the angles when the right shoulder joint extended forward and flexed backward maximally without support, and analyzed these shoulder joints and range of motion. Trial-to-trial reliability (intraclass correlations) of each joint angle was very high, over 0.98. All joint angles showed significant changes, and values in post-PL-irradiation and postlight exercise were significantly greater than that in postplacebo-irradiation. Shoulder forward flexion and backward extension angles had significantly greater change rates in PL-irradiation and light exercise than placebo-irradiation, and their range of motion angle was in the order of PL-irradiation, light exercise, and placebo-irradiation. ConclusionsIt is suggested that PL-irradiation produces almost the same effect on shoulder joint range of motion as light exercise.

Effect of Amino Acid Mixture Intake on Physiological Responses and Rating of Perceived Exertion during Cycling Exercise

This study examined the effects of an amino acid mixture supplement on physiological response and ratings of perceived exertion during submaximal cycle-ergometer exercise in 15 healthy, untrained male students. Subjects performed submaximal sustained exercise (oxygen uptake at anaerobic threshold: 54.6 ± 12.5% of maximum oxygen uptake capacity) with a cycle-ergometer ride for 60 min. after resting for 1 min. and unloaded cycling for 2 min. They drank either a 380-ml supplement containing vespa amino acids or a lemon-flavored placebo at 30 min. before starting exercise in a double-blind design. The subjects participated in both experiments over a 1-wk. interval. Oxygen uptake, respiratory exchange ratio, heart rate, ratings of perceived exertion, and plasma lactate concentration were measured during the exercise. The change-rate of respiratory exchange ratio for the Supplement group was significantly lower than that for the Placebo group at 10 min. after starting exercise. The change-rate of the ratings of perceived exertion for the Supplement group was significantly lower than that for the Placebo group at 50 min. after starting exercise. There were no significant changes in the rates in oxygen uptake, heart rate, and plasma lactate concentration between groups. We inferred that ingesting the supplement before starting exercise has a significant effect on the respiratory exchange ratio and ratings of perceived exertion during submaximal sustained exercise for 60 min. but not on oxygen uptake, heart rate, and plasma lactate concentration.