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Localization of muscle damage within the quadriceps femoris induced by different types of eccentric exercises
Author(s) -
Maeo S.,
Saito A.,
Otsuka S.,
Shan X.,
Kanehisa H.,
Kawakami Y.
Publication year - 2018
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12880
Subject(s) - eccentric , vastus medialis , isometric exercise , squat , medicine , quadriceps femoris muscle , magnetic resonance imaging , eccentric exercise , delayed onset muscle soreness , anatomy , leg press , physical medicine and rehabilitation , electromyography , muscle damage , physical therapy , physics , muscle strength , radiology , quantum mechanics
This study examined localization of muscle damage within the quadriceps femoris induced by different types of eccentric exercises by using transverse relaxation time ( T 2 )‐weighted magnetic resonance imaging ( MRI ). Thirty‐three young males performed either of the following three exercises: single‐joint eccentric contraction of the knee extensors ( KE ), eccentric squat (S), or downhill walking ( DW ) (n=11/exercise). KE and S consisted of 5‐set×10‐lowering of 90% one‐repetition maximum load. DW was performed for 60 minutes with −10% slope, 6 km/h velocity, and 20% body mass load carried. At pre‐ and 24‐, 48‐, and 72‐hours post‐exercise, T 2 ‐ MRI was scanned and T 2 values for the rectus femoris ( RF ), vastus intermedius ( VI ), vastus lateralis ( VL ), and vastus medialis ( VM ) at proximal, middle, and distal sites were calculated. Additionally, soreness felt when static pressure was applied to these sites and maximal isometric knee extension torque were measured. Maximal torque significantly ( P <.05) decreased (7%‐15%) at 24‐48 hours after all exercises. T 2 significantly increased (3%‐9%) at 24‐72 hours after all exercises, with heterogeneities within the muscles found in each exercise. Effect size and peak change of T 2 , as well as soreness, overall indicated that the proximal RF after KE and middle VM after S and DW were most affected by these exercises. The VL did not show any significant T 2 increase after all exercises. These results suggest that muscle damage specifically localizes at the proximal RF by KE and at the middle VM by S and DW , while the VL is least damaged regardless of the exercises.