Time Under Tension
Perhaps the most useful application of tempo for the general population is to use it to improve body composition and lose fat.
In April 2015, the journal Applied Physiology, Nutrition, and Metabolism compared the effect of three different lifting tempos on energy expenditure and excess post-exercise oxygen consumption (EPOC). Greater EPOC means the metabolism is elevated to a significant degree after the exercise bout—your body continues to burn calories at a greater rate for up to 48 hours after an intense workout.
The subjects were trained men who were assigned to perform a workout of 3 sets of 5 reps at 70 percent of the 1RM (1 Repetition Maximum), in the bench press using one of the three following lifting tempos:
Concentric = (Positive) Contractions: This contraction shortens your muscle as it acts against resistive force (like a weight).
Eccentric = (Negative) Contractions: Muscles lengthen while producing force—usually by returning from a shortened (concentric) position to a resting position.
• 1.5 seconds for both eccentric and concentric—15 seconds per set
• 4 seconds eccentric and 1 second concentric—25 seconds per set
• 1 second eccentric and 4 seconds concentric—25 seconds per set
Results showed that the 1.5-second tempo required the least energy to perform and EPOC was significantly less than with the other two tempos, which is not surprising since the participants spent less time under the weight. Still, this reminds us that a simple way to burn more energy before and after a workout is to mix up the tempo—and to perform more sets, of course.
Program Rest Periods to Lose Fat
Using a slower tempo, such as 4010 (4 seconds eccentric – no pause – 1 second concentric -no pause) used in the EPOC study above, will bring about more metabolic adaptations. You’ll experience increases in energy stores like creatine phosphate and muscle glycogen, but it will also produce a hypertrophic and fat burning response. The 4010 tempo was more metabolically taxing, meaning more growth hormone will be released, which is the principal hormone you want to elevate to lose fat.
A simple way to produce more growth hormone and burn fat is to use shorter rest periods between sets or sprint repetitions. Rest periods—a side variable to tempo that must be accounted for—of 60 seconds will result in significantly more growth hormone release than 90 or 120 second rest periods.
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