title: Effects of immediate vs. delayed massage-like loading on skeletal muscle viscoelastic properties following eccentric exercise.
abstract: BACKGROUND
  This study compared immediate versus delayed massage-like compressive loading on skeletal muscle viscoelastic properties following eccentric exercise.
  
  
  METHODS
  Eighteen rabbits were surgically instrumented with peroneal nerve cuffs for stimulation of the tibialis anterior muscle. Rabbits were randomly assigned to a massage loading protocol applied immediately post exercise (n=6), commencing 48h post exercise (n=6), or exercised no-massage control (n=6). Viscoelastic properties were evaluated in vivo by performing a stress-relaxation test pre- and post-exercise and daily pre- and post-massage for four consecutive days of massage loading. A quasi-linear viscoelastic approach modeled the instantaneous elastic response (AG0), fast (g1(p)) and slow (g2(p)) relaxation coefficients, and the corresponding relaxation time constants τ1 and τ2.
  
  
  RESULTS
  Exercise increased AG0 in all groups (P<0.05). After adjusting for the three multiple comparisons, recovery of AG0 was not significant in the immediate (P=0.021) or delayed (P=0.048) group compared to the control group following four days of massage. However, within-day (pre- to post-massage) analysis revealed a decrease in AG0 in both massage groups. Following exercise, g1(p) increased and g2(p) and τ1 decreased for all groups (P<0.05). Exercise had no effect on τ2 (P>0.05). After four days of massage, there was no significant recovery of the relaxation parameters for either massage loading group compared to the control group.
  
  
  CONCLUSIONS
  Our findings suggest that massage loading following eccentric exercise has a greater effect on reducing muscle stiffness, estimated by AG0, within-day rather than affecting recovery over multiple days. Massage loading also has little effect on the relaxation response.
authors.affiliation: Division of Sports Medicine, Department of Family Medicine, The Ohio State University, Columbus, OH, USA; Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
authors.forename: Scott K
authors.initials: SK
authors.lastname: Crawford
authors.affiliation: Division of Sports Medicine, Department of Family Medicine, The Ohio State University, Columbus, OH, USA; Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Haas
authors.affiliation: University of Kentucky, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Butterfield
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Center for Biostatistics, The Ohio State University, Columbus, OH, USA.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Division of Sports Medicine, Department of Family Medicine, The Ohio State University, Columbus, OH, USA; Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA; Sports Health and Performance Institute, The Ohio State University, Columbus, OH, USA. Electronic address: Tom.Best@osumc.edu.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Best
mesh_terms: D000818:Animals; D004548:Elasticity / Q000502:physiology*; D005080:Exercise Test; D008297:Male; D008405:Massage / Q000379:methods*; D008954:Models, Biological; D009126:Muscle Relaxation / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D063806:Myalgia / Q000517:prevention & control; D010805:Physical Conditioning, Animal / Q000379:methods*; D011817:Rabbits; D011897:Random Allocation; D016059:Range of Motion, Articular; D013997:Time Factors
keywords: Compression; Massage; Passive properties; Skeletal muscle; Viscoelastic