title: Effect of training on skeletal muscle injury from downhill running in rats.
abstract: Experiments were conducted to test the hypothesis that injury to skeletal muscle in rats resulting from prolonged downhill running is prevented to a greater extent by prior downhill training than by either uphill or level training. Changes in plasma creatine phosphokinase (CPK) activity and glucose-6-phosphate dehydrogenase (G-6-PDase) activity in the soleus (S), vastus intermedius (VI), and medial head of triceps brachii (TM) muscles were evaluated as markers of muscle injury 48 h after 90 min of intermittent downhill running (16 m . min -1). Prior to this acute downhill run, groups of rats were trained by either downhill (-16 degrees), level (0 degrees), or uphill (+16 degrees) running (16 m . min -1) for 30 min/day. Training duration was either 5 days or 1 day. A training effect (i.e., reduced muscle injury) was indicated if muscle G-6-PDase or plasma CPK activity in a trained group following the 90-min downhill run was not different from that of nonexercised control animals and/or if it was lower than that of nontrained runners. A significant training effect was achieved in all three muscles with 5 days of either downhill or level training, but only in S after 5 days of uphill training. Elevation of plasma CPK activity was prevented by 5 days of training on all three inclines.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D003402:Creatine Kinase / Q000097:blood; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009132:Muscles / Q000201:enzymology / Q000293:injuries*; D010805:Physical Conditioning, Animal; D051381:Rats; D011919:Rats, Inbred Strains; D012420:Running; D013997:Time Factors
chemical_list: D005954:Glucosephosphate Dehydrogenase; D003402:Creatine Kinase