title: [Application df/dt(max) index for determinations of skeletal contractility].
abstract: OBJECTIVE
  To analyze the most force rising ratio (+ dF/dt(max)) and the most force descending ratio (- dF/dt(max)) for more sensitive index of skeletal contractility.
  
  
  METHODS
  Mouse model of swimming training was used, most force (f(max)), + dF/dt(max) and - dF/ dt(max) of gastrocnemius contracting were measured and changes of gastrocnemius supermicro-structure was observed.
  
  
  RESULTS
  Mitochondria increased and myoneme was regular in general training load, gastrocnemius F(max) - dF/dt(max) significantly increased than in control (P < 0.05), + dF/dt(max) increased more significantly (P < 0.01). Mitochondria was rare and myoneme was unusual in overtraining load, gastrocnemius F(max), - dF/dt(max) reduced significantly than in control (P < 0.05), + dF/dt(max) reduced more significantly (P < 0.01).
  
  
  CONCLUSIONS
  + dF/dt(max) is better index than F(max) in judging skeletal contractility.
authors.affiliation: College of Biology, Shinaxi Normal University, Xi'an 710062, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Guo
authors.forename: Zhen-Jun
authors.initials: ZJ
authors.lastname: Tian
authors.forename: Liang
authors.initials: L
authors.lastname: Tang
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology* / Q000648:ultrastructure; D013550:Swimming / Q000502:physiology*