Use of acoustic myography in evaluation of biceps brachii and triceps brachii muscle function in nine skijoring dogs

Abstract

Abstract Studies have found pain and inflammation in the shoulder region of working sled dogs. As skijoring is a comparable, competitive winter sport, this act may result in injuries similar to those seen in sled dogs. The purpose of this study was to assess the duration of muscle contraction, temporal, and spatial summation (E-, S-, and T-scores) of the biceps and triceps brachii muscles and compare between skijoring and free-running. Nine skijoring dogs completed a free-run and skijoring trial on the same trail in random order. Acoustic myography (AMG), measuring on:off ratio (E-score), spatial summation (S-score), and temporal summation (T-score) of the biceps and triceps brachii was performed comparing the muscle work during skijoring and free-running tasks ensuring minimal acceleration during each recording period. Statistical analyses included Shapiro-Wilk tests, paired Student’s t-tests, two-way ANOVAs, and Mann-Whitney U tests. Significance was set at . When comparing the E-, S- and T-scores of the experienced dogs, the E-score of the triceps brachii was significantly lower during skijoring compared to free-running. When comparing the biceps versus the triceps in all dogs, T-score for the biceps was significantly lower than that of the triceps during skijoring. Males were significantly faster than the females during both the free-running and skijoring tasks. Males all fell in the experienced dog group. In experienced dogs, the increase in triceps workload during the task of skijoring with no apparent change in its antagonist, the biceps, could result in excess tension on the musculotendinous unit of the biceps. The relative workload of the biceps versus the triceps appears higher regarding temporal summation during skijoring.