Heart rate changes following knee extensor muscles isometric exercise and Russian stimulation.
Background. Static exercise leads to a greater heart rate increase than comparable dynamic effort, which matters in cardiovascular disorders. Neuromuscular electrical stimulation is an alternative to volitional isometric exercise. Heart rate increases following both kinds of static effort to knee extensor muscles were compared. Material and Methods. 65 healthy volunteers (33 males, 32 females), aged 20 - 22 (mean 20.94) years, completed the trial. Isometric exercise and electrical stimulation were performed randomly, with 48 hours' rest period. Each repetition's peak contraction forces were measured. Heart rate was recorded at rest and post- effort. Results. Contraction forces decreased in subsequent repetitions. First and last repetition measurements were 380.7 N (+/-6.9), 349.2 N (+/-51.9), 635.3 N (+/-120.0) and 562.1 N (+/-102.7), in females and males, respectively. In the same manner, electrically evoked contraction forces were as follows: 126.7 N (+/-84.5), 137.63 N (+/-7.1), 28.2 N (+/-102.81) and 262.2 N (+/-117.7). Heart rate increased immediately after exercise in females by 52.2 beats/min and differences (p< 0.001, p< 0.01) existed for 2 minutes during recovery. In males the increase was 56.9 beats/min and differences were significant (p< 0.001, p< 0.01) for 3 minutes post-exercise. Heart rate increased immediately after stimulation by 12,9 beats/min (p<0.001) in females and by 9,9 beats/min (p<0,001) in males. Conclusions. In young, healthy males and females, intensive voluntary isometric exercise leads to bigger and more prolonged heart rate increase than Russian electrical stimulation.
Płaszewski
Maciej
M
Wydział Fizjoterapii Wyzszej Szkoły Administracji Towarzystwa Szkolnego im. M. Reja, Bielsko-Biała.