Seasonal variations in the relationship between mid-upper arm circumference and maximum voluntary contraction among ethiopian farmers

Objectives: To determine the nature of the relationship between mid-upper arm circumference (MUAC) and maximum voluntary contraction (MVC) in pre- and post-harvest seasons among adult Ethiopian farmers. Subjects/Methods: A total of 491 healthy adult men aged 18-60 years were recruited at pre- harvest season and followed up at post-harvest season. Anthropometric measurements (weight, MUAC, biceps/triceps skinfold thickness and forearm circumference) were obtained using standard techniques and arm muscle circumference (AMC)/arm muscle area (AMA) was calculated. MVC of both arms was measured using a handgrip dynamometer. Paired t-test was used to compare means, and linear regression to investigate the relationship between MUAC and MVC. Results: Maximum voluntary contraction showed statistically significant correlation with MUAC. Grip strength (MVC) demonstrated a linear increase from under-nourished to normal subjects across MUAC classes. Paradoxically, mean MVC of both arms declined significantly during the post-harvest season. However, the relationship between MUAC and MVC held tight in the post-harvest season as seen in the pre- harvest period. Conclusions: This study has highlighted that under-nourished adult men have reduced functional ability (strength) in all seasons. In addition, strength increases in a linear fashion as MUAC increases during both seasons. More work examining the relationship between functional ability and anthropometric indices in adults from different developing countries is needed to address use and cutoffs for grip strength.