title: Cross training: indices of training stress and performance.
abstract: Twenty well-trained runners (VO2max 4.6+/-0.5 L x min[-1]) were age and ability matched and assigned to either a cross training (CT) or run only group (RT). All subjects maintained normal running distance and intensity for 6 wk and reported for three additional training sessions per week. These workouts were performed outdoors on a 400-m track or measured road course (RT) or on a bicycle ergometer (CT). The sessions were as follows: (work x rest(-1) ratio = 1): 5 x 5 min at >95% VO2max/peak (Monday), 50-60 min at 70% VO2max/peak (Wednesday), and 3 x 2.5 min at >105% VO2max/peak, plus 6 x 1.25 min at >115% VO2max/peak (Friday). Subjects were tested before (PRE), after 3 wk (MID), and after 6 wk (POST) of intensified training. Blood samples were obtained from RT, CT, and ten controls (CON) at each time point (0600 h). Runners also completed a 10-min submaximal run at the same absolute intensity (velocity to elicit 75% of initial V02max) during which heart rate, RPE, and VO2 were measured. Each runner then completed a simulated 5-km race (time trial) on a treadmill. Total testosterone (TT), free testosterone (FT), cortisol (C), and creatine kinase activity (CK) were determined. Running economy was similar between RT and CT; however, RPE decreased significantly at MID and POST compared with that at PRE (P < 0.05; time effect). There were no significant differences among groups for TT, FT, or CK, but C was significantly lower in CON than in RT and CT. Performance was significantly faster (P < 0.05; time effect) in the 5-km race at MID (1076.1+/-81.4 s) and POST (1068.6+/-83.9) compared with PRE (1096.6+/-79.5) but was not different between CT and RT. In conclusion, RT and CT responded similarly to 6 wk of increased training, and both groups improved 5-km performance to a similar extent.
authors.affiliation: Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN 47907, USA. mickflyn@purdue.edu
authors.forename: M G
authors.initials: MG
authors.lastname: Flynn
authors.forename: K K
authors.initials: KK
authors.lastname: Carroll
authors.forename: H L
authors.initials: HL
authors.lastname: Hall
authors.forename: B A
authors.initials: BA
authors.lastname: Bushman
authors.forename: P G
authors.initials: PG
authors.lastname: Brolinson
authors.forename: C A
authors.initials: CA
authors.lastname: Weideman
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D016022:Case-Control Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D010806:Physical Education and Training / Q000379:methods*; D012420:Running / Q000502:physiology; D013315:Stress, Psychological / Q000209:etiology*; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone; D006854:Hydrocortisone