Laterality of handgrip strength: age- and physical training-related changes in Lithuanian schoolchildren and conscripts

Laterality in handgrip strength was assessed by analyzing dynamometric data of the right and left hand in three samples of Lithuanian boys and girls aged 7-20 years. In addition, the influence of general physical training on the laterality of handgrip strength was explored in a sample of conscripts. A negative secular trend in handgrip strength of schoolchildren has been detected since 1965, and with increasing age, right-handedness has become more pronounced. Children that were ambidextrous (by grip strength) showed negative deviations in physical status more often than their right- or left-handed peers. During one year of physical training, the conscripts had a larger increase in grip strength of the left than in the right hand, and a marked shift in handgrip laterality toward left-handed and ambidextrous individuals was observed. The different impact of schooling and physical training on handgrip strength laterality might partly explain variations in the prevalence of handedness in different societies with divergent cultures and lifestyles (e.g., more or less sedentary).

Laterality and age-level differences between young women and elderly women in controlled force exertion (CFE)

This study aimed to examine laterality and age-level differences in maximal handgrip strength and CFE using women as subjects. The subjects were 50 young women (mean age 20.9±1.9 years) and 50 elderly women (mean age 72.9±6.6 years). The maximal handgrip strength was measured twice with a 1-min interval, and the larger value was used in this study. In the CFE test, the subjects matched their submaximal grip strengths to the demand values changing at a constant frequency (range=5-25% of the maximal grip strength). The CFE test was performed twice after one practice trial (one trial was 40s). The sum of the percent of differences between the demand value and the grip exertion value was used as an estimate of CFE. CFE was estimated using a mean from two trials, excluding the first 15s of each trial. The elderly were significantly inferior in maximal handgrip strength of the dominant and non-dominant hands to young adults (about 70%), and the non-dominant hand was significantly inferior to the dominant hand. The elderly were significantly inferior in CFE of both hands to young adults (about 50%), and the non-dominant hand was significantly inferior. In conclusion, the age-level differences in maximal handgrip strength and CFE are found in the dominant and non-dominant hands, and laterality is also found in both young adults and the elderly. The CFE relating closely to nerve function may have a larger age-level difference than maximal handgrip strength.