Background: Systematic exercise is an essential component for health promotion and improvement of the quality of life. Exercise that emphasizes on the eccentric (lengthening) skeletal muscle contractions has recently gained attention due to its benefits over conventional exercise that predominantly involves concentric (shortening) muscle contractions. The mechanical efficiency of walking on an inclined (uphill) and a declined (downhill) treadmill is equivalent to those of concentric and eccentric muscle contraction, respectively.
Objective: To compare the acute effect of uphill (concentric exercise) and downhill (eccentric exercise) treadmill walk on physical exertion and cardiovascular response.
Materials and Methods: The present crossover study involved 30 males, aged 20.6 ± 1.9 years, having a body mass index of 20.7 ± 1.4 kg/m2. Participants did an acute bout of uphill (+0.16 grade) and downhill (−0.16 grade) treadmill walk at an average speed of 4.6 ± 0.4 km/h for 30 min. Borgs 6-20 scale rating of perceived exertion (RPE), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), mean arterial pressure (MAP), pulse pressure (PP), and rate pressure product (RPP) were the study parameters. Statistical analysis was done using paired t-test or Wilcoxon test.
Results: The downhill walk caused a significant (P < 0.05) lower mean change in SBP, HR, MAP, PP, RPP, and RPE (26.7 ± 5.6, 58.2 ± 6.8, 16.2 ± 6.1, 15.9 ± 4.1, 106.3 ± 14.5, 12.5, respectively) as compared to uphill walk (22.3 ± 6.0, 40.3 ± 9.2, 12.53 ± 6.7, 14.0 ± 3.6, 74.6 ± 15.7, 11, respectively). The mean change in DBP was non-significant.
Conclusion: Moderate-intensity downhill walk at −16% grade might be preferred for exercising individuals with a low tolerance to physical and cardiovascular stress.
Key words: Concentric Exercise; Eccentric Exercise; Lengthening Contraction; Rate Pressure Product; Shortening Contraction
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