INTERACTION BETWEEN CORTISOL AND TUMOR-NECROSIS-FACTOR WITH CONCURRENT RESISTANCE AND ENDURANCE TRAINING

Objective: To determine the effect of concurrent resistance and endura nce training on tumor necrosis factor alpha (TNF alpha), urinary free cortisol, strength [one-repetition maximum (1 RM)], and maximal oxygen consumption (Vo(2)max).Design: Randomized control trial of 12 weeks' duration. Setting: University of Alberta, Edmonton, Alberta, Canada. P articipants: Forty-five healthy female (n = 18) and male (n = 27) subj ects who had not formally trained for at least 6 months prior to the s tudy but were physically active. The mean +/- SD age, height, and body mass for all subjects were 22.3 +/- 3.3 years, 1.76 +/- 9.32 m, and 7 3.4 +/- 11.6 kg, respectively. Intervention: The subjects were randoml y assigned to four groups: strength training only (S), n = 10; enduran ce training only (E), n = 11; combined strength and endurance training (SE), n = 13; and a control group (C), n = 10. The S and E groups per formed progressively overloaded training sessions three times per week for 12 weeks. The SE group completed the same strength and endurance training programs on different days (i.e., 6 days/week) for 12 weeks. Main Outcome Measures: Serum levels of TNF alpha, urinary free cortiso l, 1 RM, and Vo(2)max were measured before and after 6 and 12 weeks of training. Results: Significant increases in leg press and knee extens ion 1 RM occurred after training in both S and SE groups, but the rela tive gains in knee extension 1 RM were greater in the S group. Similar increases in Vo,max were observed in groups E and SE (p < 0.05). Cort isol was significantly increased in the SE group for women and decreas ed in the E group for men after training. TNF alpha was significantly elevated in the women of group E after training. No correlation was ob served between urinary free cortisol and TNF alpha with training. Conc lusion: These results indicate that a partial interference effect of c ompromised strength gains in unilateral knee extension of the men occu rred after concurrent strength and endurance training that could not b e attributed to an interaction between cortisol and TNF alpha in respo nse to this type of exercise.