A trend in fitness is the 20-minute or less workouts. I am certainly not opposed to these—particularly for general fitness and/or fat loss. The problem (for me—and I’d like to see other professionals speak out) is the notion that with these workouts you can eat your cake and have it too (an unkind metaphor for those of us who are struggling to shed fat pounds). That is, it is increasingly common to see claims that, with these workouts, you can “do it all”. In other words, knock out your cardiorespiratory endurance and strength training in one short—very short—workout.
First, I am going to sound the specificity horn until people listen. Muscle strength and hypertrophy come from muscle strength and hypertrophy training—high-intensity and high-volume training, respectively. Strength and hypertrophy take time and effort. Cardiorespiratory gains—i.e., increases in maximal oxygen uptake or VO2max—come from intensive aerobic exercise. High-intensity interval resistance training (HIIRT) may have marginal benefits for cardiorespiratory fitness, and the benefits for fat-loss (e.g., prolonged post-exercise energy expenditure or “calorie burn”) are well-established. Claims of increased muscle hypertrophy and, especially, strength (except in the initially untrained) are simply unfounded.
Back in its heyday, Nautilus-type training (e.g., one set to momentary muscular failure for 10-12 whole body exercises performed in the repetition ranges of 8-16 repetitions) demonstrated some positive effects on strength and hypertrophy. The benefits on cardiorespiratory fitness were minimal (despite the elevated heart rate and fatigue).
Today, everyone wants to label his or her HIIRT workout “Tabata”. The fact is, few can actually execute a true Tabata IE1 protocol (8 repeated bouts of cycling for 20 seconds at 170% of VO2max followed by a 10-second recovery—4 minutes in total). It is important to note that the 1996 study by Tabata and co-workers included 4 intense training sessions per week and an additional day of steady-state exercise. Participants were Olympic speedskaters who were eliminated from the study if they could not maintain the intensity. So, we “average” folk are even less likely to be able to perform this level of exercise. Moreover, the HIIRT protocols, commonly labeled as “Tabata” are nowhere near this intensity level and, thus, not at all likely to produce notable improvements in aerobic fitness.
If you want to “have it all”, you are going to have to work harder than 20 minutes a few times a week. If you want general health and fitness, then, by all means, give HIIRT a try.
My suggestion? If you want to have it all, invest 6-12 exercise sessions a week on specific training—splitting your time between goal-specific weight-training, steady-state cardio and/or HIIT (using an aerobic modality), and HIIRT (for fat burning and motor skill-related fitness). This will still result in more general fitness, but the gains will be more significant. If you want even more, then plan to invest significantly more time into the workouts, recovery, and diet.
Don’t buy the fantasy of 20-minute workouts (unless you are training 2 to 6 times a day). There are no short-cuts to fitness. Time-efficiency and effective only go together when there is significant effort in the formula.
Be your best today; be better tomorrow.
Carpe momento!