Tracking handgrip strength in Kendo athletes from university to middle and older adulthood.

OBJECTIVE: This study aimed to compare the current handgrip strength (HGS) of Kendo athletes with their HGS when they were in university (up to 50 years). METHODS: Eighty male graduates who were Kendo club members during their university days performed anthropometric and HGS measurements, and these HGS were compared with those measured during their university days (mean age of 19.5 years old). RESULTS: There was no evidence of a statistical difference in HGS between the current measurement and the measurement taken during university [-0.64 (-1.9, 0.67) kg, p = .336]. There was, however, evidence that the difference in HGS depended upon the current age of the individual (t = -6.43, p < .001). When probing the interaction, there were statistical differences between the ages of 24.6 and 38.2 years and between the ages of 47.4 and 69.9 years. Strength increased across time in the younger participants and decreased for those who were older. Between the ages of 38.9 and 46.1 years, there was no evidence of a statistical difference indicating a maintenance of strength. CONCLUSION: The HGS of Kendo club graduates, which they acquired during their formative years, continued to increase even after they graduated from university and entered their 30s. However, their HGS decreased from age 50, even though they practiced Kendo.

Sports and Kinetic Visual Acuity.

Kinetic vision acuity (KVA) is an index developed in Japan that refers to the capacity to recognize a moving object that moves back and forth against the observer. This review outlines the history of KVA and studies on KVA conducted at the Faculty of Health and Sports Science of Juntendo University, i.e. characteristics of KVA in athletes, factors associated with KVA, sports and age-dependent decline of KVA, and effects of docosahexaenoic acid (DHA) and astaxanthin on KVA. KVA was defined in the early 1960s, and the measurement device was invented in 1968. Studies at the Faculty of Health and Sports Science began in the 1990s. In track-and-field athletics and skeleton, a winter downhill event, higher-ranked athletes had higher KVA than lower-ranked athletes. Although KVA cannot be predicted from static visual acuity or reaction time, a significant correlation was found between KVA and the peak latency of visual-evoked potentials. KVA could not be improved by training and did not change between age of 8 and 17 years. In contrast, habitual practice in kendo may inhibit the age-dependent decline in KVA. DHA may also improve KVA in subjects with low KVA; however, astaxanthin did not improve KVA.