Effects of Strength Training Assessed by Anthropometry and Muscle Ultrasound

Improving and maintaining an ideal body composition is important for sporting achievement and good health. Body composition assessment is therefore a tool used to monitor training and to evaluate the objectives of a training plan for health purposes. Ultrasound (US) emerges as an alternative to evaluate the thickness of subcutaneous cellular tissue, as well as muscle thickness: (1) Background: We aim to evaluate and compare the anthropometric and ultrasound measurements used to quantify the effects of strength training. (2) Methods: A total of 31 students (22.3 ± 4.14 years of age), 25 men and 6 women, from the Professional Programme in Sport were enrolled in the Physical Preparation course at the Institución Universitaria Politécnico Colombiano Jaime Isaza Cadavid. Protocol: Pre- and post-intervention ultrasound and anthropometric evaluations of a strength training programme with a predominance of the eccentric component were performed three times a week for 4 weeks. For the pre- and post-intervention relationship of the quantitative anthropometric and ultrasound variables, the Wilcoxon signed-rank test was used; the effect size of a Wilcoxon test was also calculated using the rank correlation, and the correlation of the anthropometric and ultrasound variables was determined using Spearman's correlation coefficient, with a <i>p</i>-value < 0.05 considered statistically significant. (3) Results: There were no statistically significant differences in the anthropometric variables assessed, but there were significant differences in measures of quadricep muscle size and in the control parameter echo-intensity (EI) of subcutaneous fat in the variables. (4) Conclusions: The US of the quadriceps can measure changes in muscle thickness even without changes in muscle mass assessed by anthropometry, making it an excellent tool for the evaluation and monitoring of strength training.