Purposes: The purposes of this study were: (1) to compare the grip strength and plantaflexor strength between young and old adults by using clinical muscle testing techniques; (2) to examine the effects of gender and limb dominance on muscle strength; (3) to examine the correlation of the grip and plantarflexor strength; and (4) to investigate the distribution of grades of plantaflexor muscle strength in the old adults. Methods: Thirty young adults (average=26.6 years; 15 males, 15 females) and 32 old adults (average=72.6 years, 16 males, 16 females) participated in this study. Grip strength was measured using a hand-held grip dynamometer Each subject made three maximal voluntary contractions, and the average score was calculated for each hand. Plantaflexor muscle strength was measured with the standing heel-rise test, and the number of repetitions of heel-rise was recorded for each leg. Results: Male subjects showed greater grip strength than females, and the difference w as more obvious in the young adults than in the old adults. The grip strength of the dominant side was greater than that of the non-dominant side, and the difference was more obvious in the young adults than in the old adults. The number of heel-rises of the young adults (mean=l7.9 repetitions, median=l8 repetitions) was significantly higher than that of the old adults (mean=5.8 repetitions, median=5.8 repetitions, p＜0.05). There was significant but weak correlation between the grip strength and plantarflexor strength (r=0.3; p＜0.05). When the number of heel-rises was converted into the grades of the manual muscle testing, 91% of the old adults were given the fair grade (1 to 10 repetitions). Conclusions: Significant differences in grip and plantaflexor muscle strength were found between young and old adults. The majority of the old adults were ranked the same manual muscle grades for the plantaflexor muscle. It is recommended that the number of heel rises be used in place of manual muscle testing grades for the plantaflexor muscle in the old adults.