What Are The Effects Of High-Intensity Training?

What Are The Effects Of High-Intensity Training?

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Background On High-Intensity Traning

High intensity, short rest exercise is commonly used in swimming and dry-land. This demanding form of training is believed to influence different energy systems with minimal research.

This form of training has gained much praise almost solely on anecdotal research but is more commonly seen in dry-land and fitness enthusiast. Popular commercial programs of this variety include HIIT, CrossFit®, and Insanity®. These forms of exercises are vastly different than the traditional periodization programs suggested by strength and conditioning certifications. Even though short rest training is not new, the associated high intensity (approximately 25% higher intensity) is novel and has a high potential for overtraining or overreaching.

This study evaluated the physiological effects of an acute, high intensity (75% 1 RM), short rest resistance exercise protocol.

What was done

Nine trained men and nine trained women performed a pyramid scheme of back squat, bench press, and deadlift, beginning with 10 repetitions each, then 9, then 8, and so on until 1 repetition on the final set. If the subject was unable to perform with correct form, then the weight was decreased by 5% 1RM. Diet was controlled the day of the test with a standardized breakfast with 20/35/45 protein/fat/carbohydrate ratio.


Significant time effects were noted on lactate and cortisol, with significant sex effects observed in lactate response, but not in cortisol response. Total work was higher in men and directly correlated with lactate, but not cortisol. The average volume of lactate and cortisol were considerably greater than those produced in typical resistance exercise programming.


The results suggest relative intensity and rest period length are important factors that determine metabolic and adrenal stress.

Practical Implication

The associated increase in lactate and cortisol can be used to manipulate a dry-land or swimming program. However, this should be monitored closely and regulated accordingly to allow adequate recovery from high-intensity training. Make sure to progress your athletes to these high workloads, to prevent overtraining and injury.

This study only looked at the short-term effects of short rest, high-intensity training. Further research is necessary to understand long-term effects, specifically on the cellular level.


  1. Szivak TK, Hooper DR, Kupchak BK, Apicella JM, Saenz C, Maresh CM, Denegar CR, Kraemer WJ. Adrenal Cortical Responses to High Intensity, Short Rest, Resistance Exercise in Men and Women. J Strength Cond Res. 2012 May 3.

Originally Posted June 2012

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