by Evie Ullman, DPT
If you work out, you may have heard of these two fitness trends by now. What exactly are they?
Let’s begin with Crossfit: a workout regimen comprised of constantly varied high intensity functional movements. A typical Crossfit workout will take about an hour, with about 20-30 mins of very high intensity exercise and it is done as a boot camp, so to speak, lead by a trainer. Each day the workout is different. An individual workout is known as a “WOD” or Workout of the Day. There could be as few as 2, or up to a dozen different components in a single WOD. The class goes through a warm-up, the WOD, and then a cool down/stretching period. What happens during the WOD? Well, the answer is any number of things. It is a mishmash of aerobic, body weight, gymnastic and Olympic weight lifting exercises, typically with little to no rest between exercises.
Are you confused enough yet? Crossfit trainers and enthusiasts have created several WODs with different names. Here are a few WOD examples that will give you a better idea of what goes on during a Crossfit workout:
WOD for Beginners: (5 rounds):
- 10 sit-ups
- 10 pushups
- 10 squats
WOD “Badger:” (3 rounds for time):
- 95lb squat clean x 30 reps
- 30 pull-ups
- run 800 meters
WOD “Candy:” (5 rounds for time)
- 20 pull-ups
- 40 pushups
- 60 squats
Other elements in a Crossfit workout could include things like rope climbing, box jumps, flipping over tires, kettle bell swings, ring dips—you name it. The goal of Crossfit is to force the participant to perform exercises that work on endurance, strength, flexibility, power, speed, agility, balance, coordination and accuracy so that they make gains in each of these domains of fitness. That is Crossfit, in a nutshell.
Now, what about Tabata?
During the mid 1990s, an exercise scientist named Izumi Tabata used a very specific form of high intensity interval training and obtained excellent results with his subjects. After 5 days per week for 6 weeks of the set high intensity interval training, their aerobic capacity improved by 14% and their anaerobic capacity improved by 28%, while the control group, who only performed moderate intensity cardio for the same amount of time, only made gains in aerobic capacity, not in anaerobic capacity. Anaerobic fitness contributes a great deal toward building and supporting lean muscle mass, which aids in body fat loss by boosting metabolism.
The specific interval training routine of Tabata is this: 20 seconds of exercise at 170% VO2max and 10 seconds of rest for 7-8 sets. (Total actual workout time is about 4 mins). Subjects in his original study were on exercise bikes, but the Tabata method can be performed with other modes of cardio aerobic exercise (running, swimming) or medleys of exercises such as those used in Crossfit- pushups, squats, burpees, etc.
Sometimes Tabata is touted as a “4 minute miracle weight loss workout” but do not be fooled. You still have to work for well over 4 minutes to burn a significant enough number of calories for weight loss. However, you will lose weight faster if you perform a 30 minute session on the elliptical using Tabata intervals vs. just 30 minutes of medium effort, because you will burn more calories overall.
The Tabata method of working out is indeed backed by scientific evidence since it is based on a scientific study. Crossfit, however, is not. The programming for Crossfit is all over the map. Since it is a form of high intensity interval training and participants are pushed well above and beyond what they would normally do at the gym, they do get noticeable weight loss and fitness results. Crossfit does however tend to produce a lot of injuries. Take the typical 40-something gym-goer. He or she might perform 30 mins of cardio on the elliptical and a circuit of moderate intensity weight training, on Cybex machines, a few times per week. Throw that same gym-goer into a Crossfit class and watch them wrench their shoulders while performing max intensity rapid pull-ups and overhead presses, and you wind up with bilateral rotator cuff tears. A safer way to workout would be to simply apply the Tabata method to the existing familiar exercise routine (elliptical, Cybex). In defense of Crossfit, the exercises are adaptable (pull-ups become assisted pull-ups for those who cannot perform them, etc) and trainers check form. However, form will inevitably break down as the exerciser approaches their absolute limit, which is the work zone that Crossfit wants you to be in, through pretty much the entire WOD.
In order for your body to adapt and change and get results from working out, you need to introduce it to new stressors and Crossfit, Tabata and any other form of high intensity interval training can be a great way to do that if you proceed with caution.
Dr. Ullman is a Physical Therapist at Boston Sports Medicine
