|BodyPump is a fast paced workout with barbells. Light(er) weights, high reps, loud music and a drill instructor... if you know one, you'll know all of these group based "resistance training" workouts.|
While exercise and the exercise-induced increase in energy-expenditure is an important pillar of diet (+ exercise) induced weight loss. The dietary component is what makes you lose weight, while the exercise component is meant to (a) maximize the retention of lean muscle tissue and (b) improve your overall fitness and health. If you're just "working out to burn energy" you're destined to fail; not least because you will never be able to tell exactly how many kcals you've "left in the gym". And beware: Especially while dieting, it's usually much less than you think ;-)
- People overestimate the energetic demands of "intense" exercise (Berthiaume. 2015) - In view of the fact that everyone knows the (inaccurate) rule of thumb that says that the amount of energy (in kcal) you expend when you're jogging is roughly your body weight times 10 (it's actually rather body weight times 7, unless you're running really fast, by the way), it's not surprising that Berthiaume et al.'s latest study shows that their subjects, 40 healthy men and women (age: 31.7±5.8 years, body mass index [BMI]: 24±2.6 kg/m²), significantly overestimated the amount of energy they expended during a (perceived) "intense" BodyPump(TM) workout.
Figure 1: Young, healthy BodyPump practitioners overestimate the energetic demands of this kind of equipment based group workouts by over 36% (Berthiaume. 2015). Figure 2: Just a reminder: The energy expenditure (kcal per kg of body weight per hour) due to body weight exercises calculated based on oxygen uptake during the exercises (traditional) or during the rest periods has been shown to be rather under- than overestimated (Vezina. 2014 | read more)
- Exercise type and post-workout supplementation influence post-exercise resting energy expenditure and respiratory exchange ratio (Wingfield. 2015) - I know, I have written about EPOC, which is actually nothing else than the total post-exercise energy expenditure in relation to the respiratory exchange ratio, repeatedly. There is a reason, though, that the latest study from the University of North Carolina still made it into the SuppVersity news: It compared six exercise sessions, consisting of three exercise modalities and two acute nutritional interventions - that's extraordinary, for sure.
- AEE - aerobic endurance exercise - 30-min on the treadmill at 45% to 55% of the heart rate reserve), high-intensity interval running
- HIIT - ten rounds of a 60-s treadmill run at 85% to 95% HRR with a 60-s passive rest period), and
- HIRT - high-intensity resistance training consisting of leg presses and bench presses, lunges, shoulder presses, biceps curls, and triceps extensions using free weights for three sets of 6RM to 8RM followed by a 20- to 30-s rest for each set of a given exercise and 2.5 min between each exercise
- CHO and PRO (25 g of CHO (maltodextrin) or PRO (whey isolate) mixed with 6 oz of water in an opaque bottle.
Figure 3: Overview of the study design (Wingfield. 2015). Figure 4: Only the HIIT modality yielded sign. inter-group differences as far as the resting energy expenditure is concerned. Even those were very transient, though, and disappeared 30 min after the workout (Wingfield. 2015).
Cortisol is not your enemy - at least in the short run: As expected the hardest workout, the HIIT workout, produced the most significant increase in cortisol. The change was still not statistically significant, but I decided to mention it anyway, in order to take the chance and remind you of the fact that cortisol is a glucocorticoid that will not just gnaw away your muscles (it does so if it's chronically elevated), but is also involved in a host of beneficial processes including acute increases in performance and the facilitation of body fat loss (learn more).
- What is less surprising is the relatively small, but "significant" (statistically, only!) increase in REE in response to protein vs. carbohydrate (Figure 4, B). So, protein is thermogenic even after a workout. Unfortunately, the increase in energy expenditure and the increase in fatty oxidation as signified by the reduced respiratory exchange ratio in Figure 5 B are way too small to be of any practical relevance.
Figure 5: Effect of exercise modality and CHO vs. PRO supplement on the respiratory exchange ratio (RER); lower values indicate greater fat and lower carbohydrate oxidation (Wingfield. 2015).
- Berthiaume, M. P., et al. "Energy expenditure during the group exercise course BodypumpTM in young healthy individuals." The Journal of sports medicine and physical fitness 55.6 (2015): 563.
- Vezina, Jesse W., et al. "An Examination of the Differences Between Two Methods of Estimating Energy Expenditure in Resistance Training Activities." Journal of strength and conditioning research/National Strength & Conditioning Association (2014).
- Wingfield, et al. "The acute effect of exercise modality and nutrition manipulations on post-exercise resting energy expenditure and respiratory exchange ratio in women: a randomized trial." Sports Med Open. (2015)