We performed electromyographic observations of M. deltoideus, M. biceps, M. triceps brachii, and extensor and flexor muscles of the right forearms of four healthy males (22.3 years old average) during various exercises of the right upper extremity on ground and in water. All electromyographic activities were examined through integral analysis. During exercise in water, the proximal part of the upper arm showed a significantly lower electric discharge than that for the exercises on the ground (p<0.05). Furthermore, forearm muscles showed significantly higher electrical discharge than that for the same exercise on the ground (p<0.05). We investigated the effects of therapeutic exercises in water in a temperature-adjusted pool on 15 female patients with rheumatoid arthritis (average 48.0 years old, Stage 2.3, and Class 1.9). The respiratory function, dorsal muscle power, power around a knee, grasping power, elasticity of the trunk and lower extremities, Lansbury index, and Japan Orthopedic Association's judgment score for rheumatoid arthritic knees were improved significantly (p<0.05) after an eight-week course of therapeutic exercises in water (two session a week). The result of a psychological test showed that their mental conditions were significantly improved (p<0.01) by therapeutic exercises in water. No aggravation of inflammatory reactions was observed in serological examinations before and after the exercise. We concluded that therapeutic exercise in water was an effective treatment method for patients with rheumatoid arthritis.

We subjected six male lumbago patients (average age of 58.2 years) to underwater therapeutic exercise with and without a hydropower system (Flow Machine (FM)) twice a week for 4 weeks (a total of 10 hours) at an interval of 10 weeks between the two therapeutic sessions. The FM produced running water (average speed of 0.9meter/second) in a temperature-controlled pool. The water temperature was kept to about 30°C, The subjects received a total of four examinations before and after these two therapeutic sessions. We compared the results of these two therapeutic sessions (under-water therapeutic exercise with FM and without FM) and obtained the conclusions described below.
Improvements of obesity, anaerobic power, power around knee, vital capacity and total score in lumbago treatment (results of Japanese Orthopaedic Association) were observed more significantly (p<0.05) and rapidly with the use of FM than without FM. Further, increased HDL-cholesterol and decreased free fatty acid in blood were observed significantly (p<0.05) only for FM use.
It was suggested that the resistance of running water, vibratile massage effect, and heat action of produced supersonic waves promoted the above improvements. We concluded that the hydropower system was useful in underwater therapeutic exercise on lumbago patients.

Underwater exercise for ordonary adult lumbago patients (5 males, 5 females) and athletes with lumbago (11 males) was carried out.
The mean ages of ordonary adult lumbago patients and athletes with lumbago were 47.1 yr, and 20.1 yr respectively. The underwater exercise was conducted twice a week for three months.
The results obtained were as follows:
1) The values of VO₂max tended to be increased in both groups. The value of back strength in the ordinary adult lumbago patients became significantly higher than the basal value.
2) Lumbago treatment score as assessed by the Japanese Orthopedic Association (JOS-score) and the results of the spinal function test (K-W test) were improved significantly in both groups of patients.
3) The values of knee flection and extension strength in the ordinary adult lumbago patients became significantly higher than the basal values, however, in the athletes with lumbago, became only the knee flection strength became significantly higher than the basal value.
4) The results of the spinal function test (K-W test) and all muscle strength tests in athletes with lumbago were improved to a greater extent than in the ordinary adult lumbago patients.
The present results suggest that lumbago can be significantly improved after three months of underwater exercise compared with that at the start of the exercise program in both ordinary adults and athletes with lumbago.

We investigated the effects of underwater exercise plus hot-spring bathing on middle aged people.
Twenty-five subjects (mean age: 59.6±8.9 years) were divided into three groups (A, B, and C) and examined. Group A (three males, seven females) was subjected to underwater exercise and hot-spring bathing. Group B (eight females) was subjected to underwater exercise and fresh water bathing. Group C (seven females) was a control group (no exercise and no bathing).
Group A and B performed underwater exercise consisting of underwater walking, basic exercise, and swimming for 70 minutes. Group A was then subjected to hot-spring bathing (sodium bicarbonate spring, PH 8.0, 39°C) for 20min, and while Group B was subjected to fresh-water bathing (30°C).
Blood pressure was measured and blood tests were conducted early in the morning on the day of exercise plus bathing and on the following day. Further, Profile of Mood Status (POMS) tests were also conducted on the day following the exercise with bathing and data were compared.
The findings were as follows.
1) On the day following the exercise plus bathing, group A (underwater exercise plus hot-spring bathing) had significantly lower diastolic blood pressure, total cholesterol, CD4, red blood cells, hematocrit and total protein when compared with values before treatment (p<0.05).
2) After the exercise plus bathing, group A (underwater exercise plus hot-spring bathing) had significantly lower levels of depression-dejection, anger-hostility and confusion in POMS tests when compared with those of Group C (control group, no exercise and no bathing) (p<0.05).
We concluded that underwater exercise plus hot-spring bathing has good effects on the health of middle aged people.