We constructed an arm holder for muscle exercise from a forearm-shaped plastic shell and magnetic resonance (MR) imaging position markers and determined the echo time (39 ms) for T 2 -weighted spin-echo MR imaging from T 2 values of the exercised (50 ms) and resting (32 ms) muscle at 0.2 tesla. The smallest detectable muscle was the extensor digiti minimi muscle (cross-sectional area 25 mm 2 ). This combination could be useful to monitor finger exercise in patients undergoing physical therapy.

Purpose: In order to detect exercised muscles by the increase in T 2 , we have defined a Gaussian T 2 distribution and reference values (T 2 r and SD r ) in resting state muscles, and a threshold for detecting exercised muscles. Methods: The subjects were healthy adult volunteers (14 males and 12 females). Multiple-spin-echo (MSE) MR images were obtained with 10 TE values from 10 to 100 ms using a 0.2T MRI system. T 2 values for 10 forearm muscles were obtained in the resting state and after isometric wrist flexion exercise with 5%, 15%, and 25% of the maximum voluntary contraction (MVC). Z values were obtained by (T 2 e − T 2 r )/SD r , where T 2 e was T 2 after exercise. Based on sample size calculations, three thresholds ( Z T = 1.00, 2.56, and 3.07) were applied to agonist and antagonist muscles. Results: A normal distribution of T 2 was detected in resting muscles at 34 ± 3 ms (mean ± standard deviation [SD]) in 26 subjects using the Kolmogorov–Smirnov test, the Shapiro–Wilk test, and the Jarque–Bera test ( P > 0.05). No gender differences were shown between the T 2 or SD, and a similar result was obtained in 12 measurements on a single subject ( P < 0.01). The T 2 r and SD r were used for reference values. The threshold Z T = 1.00 showed the highest sensitivity (0.86) even with 5% MVC, but it showed a lower specificity (0.85) than the other thresholds. Z T = 3.07 showed the highest specificity (1.0), but it showed a lower sensitivity (0.36) with the 5% MVC, compared with Z T = 2.56 (0.50). The receiver operating characteristics analysis also supported these results. Conclusion: We found that the T 2 distribution in muscles was Gaussian, suggesting that a one-sample t -test can be applied, and that Z T = 2.56 could cover low-intensity exercise with high specificity and a low false-positive rate.

Abstract. [Purpose] This study examined the adjustment of work load in the sit-to-stand exercise (STSE). [Subjects] The subjects were twenty-nine healthy young males, average age of nineteen.[Methods] Subjects did STSE and cycle ergometer exercise on the same day. The STSE protocol was standing-up frequencies set from 6 to 30 (times per minute),with an exercise time of three minutes at each frequency. The anaerobic threshold (AT) was determined on a cycle ergometer with a ramp protocol. The items measuring work load were oxygen uptake and heart rate. Cardiopulmonary function was measured from resting time to the end of the exercise. Oxygen uptake volume and heart rate relative to their AT values were calculated.[Results] Oxygen uptake volume and heart rate relative to their AT values frequencies from 6 to 30 times per minute ranged from 45.9 to 119.8 (%), and from 67.6 to 106.9 (%), respectively.[Conclusion] In case of STSE, the work load intensity of a subject cannot be quantitatively determined. Heart rate and oxygen uptake at standing exercise frequencies setting from 6 to 30 times/min relative to their anaerobic threshold values were 67.6-106.9 (%) and 45.9-119.8 (%), respectively. It was clarified that 30 times or less were anaerobic threshold that corresponded to work load . It is appropriate to adjust work load based on this standing up frequency only for young subjects.

Abstract. [Purpose] This study examined physical and cognitive factors associated with falls by the elderly. The authors hypothesized that, elderly people who experienced at least one fall in the past 12 months would show delayed probe reaction time (P-RT) during walking compared with elderly people with no history of falls.[Subjects] The subjects were 101 elderly people (27 males, 74 females), and the subjects were divided into two groups: a Fall group and a No-fall group.[Methods] We evaluated the probe reaction time, Trail Marking Test Part-A (TMT-A), Timed Up and Go Test (TUG), walking speeds at a selfdetermined pace, and the gait cycle time.[Results] The Fall group showed longer P-RT, TMT-A, TUG times and slower walking speeds than the No-fall group and its coefficient of variation (CV) of the time for a gait cycle was increased. In logistic regression analysis with fall as the dependent variable, the probe reaction time was identified as an significant factor, and the cut-off value of the probe reaction time was 406 ms as evaluated by the Receiver-Operating-Characteristic (ROC) curve.[Conclusion] It was found that probe reaction time is both reliable and useful for the evaluation of the fall risk for the elderly.