Study aim: To compare the effects of 6-week isokinetic and isotonic training programmes on heart rate and blood pressure in high school students.

Material and methods: Twenty-nine healthy, untrained male student subjects aged 15 - 18 years participated in the study. They were assigned into 3 groups: control (C; n = 11), and subjected to isokinetic (IK; n = 8) or isotonic (IT; n = 10) training lasting 6 weeks, 3 days a week. Isokinetic exercises consisted of 3 sets of 20-s extensions/flexions (both knees) at 180°/s, spaced by 30-s intermissions, the isotonic ones - of 4 sets of extensions (both knees) at 50% of the predetermined one repetition maximum, spaced by 30-s intermissions. Heart rates (HR) and blood pressure were determined before and after the training period, both pre- and post-exercise.

Results: Mean resting HR and exercise-induced HR-increase significantly decreased post-training in IT group (by 19 and 24%, respectively; p<0.001). The exercise-induced HR-increase significantly increased post-training in IK group (by 17%; p<0.001). Significant (p<0.01) training-induced decreases in the systolic pressure (SBP) were found in both training groups (IT and IK, by 7 and 6%, respectively).

Conclusions: The results may be of practical importance for athletes and health professionals who administer openchain resistance exercises.