RESUMEN
Introduction: Sudden strenuous exercise (SSE) has previously been shown to result in electrocardiograph (ECG) abnormalities indicative of myocardial ischemia when not preceded by a warm-up. Athletes regularly undergo SSE and are often unable to warm-up immediately prior to competition. It is unknown whether a delay post warm-up will result in the same heart rate (HR) response to SSE as seen with no warm-up. Aims: To compare the HR response and to observe for ECG abnormalities during SSE with a warm up, with a delay after warm up and without a warm up. Methods: Seven male subjects randomly completed three SSE exercise conditions while being monitored by ECG; a 15 second supramaximal sprint following three conditions: no warm up (NW); immediately following a warm-up (WU); and following a 10-minute delay post warm up (D). There were no ECG abnormalities across any of the conditions indicative of myocardial ischemia. Results: Significant differences (p<0.05) were found in the HR response for all time periods during exercise between WU and NW, between WU and D, but not between D and NW. A delay between warm-up and SSE resulted in a lowered HR response to the SSE compared with a warm-up immediately preceding, but a higher HR response to SSE with no warm-up. Conclusion: The findings of this study suggest that a 10 minute delay following warm-up before SSE is too long to maintain the benefits of warm-up.