The Relationship of Early versus Two-Minute Recovery Echocardiographic Values Following Maximal Effort Resistance Exercise
14 March 2008 (online)
Two-dimensionally directed M-mode echocardiography was used to measure left ventricular systolic function following maximal dynamic resistance exercise (RE). Upright measurements were made from the long axis parasternal view at rest, 20 seconds post-exercise, and two minutes post-exercise. Thirty-two successful studies were recorded from a total of 37 trained and untrained male subjects who were heterogeneous as to mode and level of training. Resistance-trained men averaged 3.8 ± 2.4 yrs of training for 9.7 ± 3.0 hr/wk, and endurance-trained men averaged 6.4 ± 3.9 yr of training at 202.5 ± 112.6 km/wk of cycling, running, and swimming. The trained men competed at the state or regional level. The RE protocol (knee extensions) was performed as follows:
Set 1 (10srest) Set 2 (10srest) Set 3 60% 1-RM @ 8 reps 60% 1RM @ 8reps 60% 1-RM to fatigue
The RE protocol produced significant post-exercise reductions in end-systolic diameter (p < 0.0002) and significant post-exercise increases in fractional shortening (p < 0.0001) and velocity of circumferential fiber shortening (p < 0.0002). The inotropic variables were still significantly different at two minutes post-exercise compared to the 20 second measure, suggesting that early recovery is a better approximation of maximal values. Velocity of circumferential fiber shortening at 20 seconds and two minutes was significantly correlated (r = 0.39) and fractional shortening was not (r = 0.34) at these serial measurement times. This study indicated that velocity of circumferential fiber shortening was a better index than fractional shortening of maximal performance at two minutes of recovery, but since all correlations are low, neither variable at two minutes post-exercise was suitable as an index of maximal performance. Further, because of phasic changes in cardiac loading during and immediately post-resistance exercise, extrapolation to maximal values may be tenuous.
Post-exercise echocardiography - resistance exercise - left ventricular function