o:26133 Quadriceps femoris cross-sectional area and specific leg strength: relationship between different muscles and squat variations en Abstract: Background. The aim was to determine the relationship between the cross-sectionalarea of the quadriceps femoris and strength performance in the deep and parallel barbellsquat.Methods. The sample included 16 university students (seven female, 24.1±1.7 years).Muscle strength was expressed as external load, including the one-repetition maximumand the body mass segments involved (calculated according to Dempster’s method).The cross-sectional area of the quadriceps femoris muscles was determined usingultrasound, while leg muscle mass was measured using the Bioelectrical Impedancemethod.Results. The cross-sectional areas of the three vastii muscles and leg muscle massshowed moderate to strong correlation with external load in both squat types (r=0.509–0.873). However, partial correlation (cross-sectional area of quadriceps femorismuscles were controlled) showed significant association only between leg muscle massand deep squat (r=0.64,p<0.05). The cross-sectional area of the vastus lateralisshowed a slightly higher correlation with external load in the parallel than in the deepsquat (r=0.67,p<0.01vs. r=0.59,p<0.05). The regression analysis extracted thevastus medialis cross-sectional area as the most important factor in manifesting strength(parallel squat:R2=0.569; deep squat:R2=0.499, bothp<0.01). The obtained resultssuggest that parallel squat strength depends mainly on the cross-sectional area of thevastii muscles, while it seems that the performance in the deep squat requires anadditional engagement of the hip and back extensor muscle groups. https://peerj.com/articles/12435/ Keywords: Range of motion, External load, Bioelectrical impedance, Dempster’s method, Deepsquat, Parallel squat 1552099 10.7717/peerj.12435 1552101 2167-8359 2022-06-27T13:17:28.019Z 44 yes 46 Филип Којић Универзитет у Београду Учитељски факултет 0000-0001-6740-3347 application/pdf 595625 https://phaidrabg.bg.ac.rs/o:26133 no yes 18 70 92000001 11A42 PeerJ – the Journal of Life & Environmental Sciences 1 15 PeerJ 2021 https://peerj.com/life-environment/