Effects of Crossfit

(Originally posted on: 11-18-2013)

Crossfit is a very popular form of fitness training Effects of Crossfitwhich aims to improve all aspects of fitness. Crossfit constantly varies exercises from Powerlifting, bodyweight exercises and kettlebell training. This is combined with different forms of cardiovascular training. Because Crossfit emerged fairly recently, little research has been performed up until now. Scientists from the Ohio State University therefore performed a study on the effects of Crossfit on aerobic endurance, fat percentage and muscle mass.

What did the researchers do? 

The researchers recruted 23 men and 20 women that were already training in a local Crossfit Box and therefore already had experience with Crossfit workouts. Before the participants started the 10 week training period, body composition was measured using a BodPod and scales. This allowed the researchers to keep track of changes in weight, BMI, body fat percentage and fat free mass. In addition, aerobic endurance was measured using a VO2Max test. These tests were repeated at the end of the 10 weeks of training.

The subjects trained five days a week for 10 weeks following a Crossfit program. Since one of the defining characteristics of Crossfit is constantly varying exercises, no single training was the same. However, almost all workouts started with a strength training session or skill training. The strength sessions were aimed at improving strength in traditional Powerlift exercises such as the squat or deadlift. The skill sessions were aimed at improving technique or balance in exercises such as ringdips or 1 legged squats. After the strength or skill session followed the Workout of the Day (WOD for the initiated) in which a certain training had to be performed as quickly as possible to set the best time, or to perform as many rounds as possible during a set amount of time. For a complete overview of the workouts used in this study, the interested reader is refered to the original article. All training sessions were supervised by certified Crossfit trainers and an exercise physiologist.

In addition to training, all subjects followed the Paleolithic diet. In short this means that they only ate food that our hunter-gatherer ancestors had acces to. This includes fish, meat, vegetables, fruit and nuts. All subjects followed this diet before starting this training period and maintained it throughout and after the 10 weeks.

What were the results?

The results of the study are depicted in the figures below. Due to the physical differences between men and women the results are depicted seperated by gender.

Crossfit effects on VO2max

Figure 1: Effects of 10 weeks of Crossfit training on VO2Max.













Crossfit Effects of 10 weeks body weight

Figure 2: Effects of 10 weeks of Crossfit training on body weight.












Crossfit effects on BMI

Figure 3: Effects of 10 weeks of Crossfit training on BMI.












Crossfit effects body composition

Figure 4: Effects of 10 weeks of Crossfit training on body composition.












Crossfit effects on lean mass

Figure 5: Effects of 10 weeks of Crossfit training on lean mass.












After finishing 10 weeks of Crossfit training both men and women improved similarly in endurance and fat percentage. Improvements in lean mass, body weight and BMI were relatively small yet significant.

Men Women
VO2Max +9.0% +9.6%
Body Weight -3.8% -2.6%
BMI -3.9% -2.8%
Fat Percentage -18.9% -12.8%
Lean Mass +1.4% +2.2%

Table 1: Relative changes as a result of 10 weeks of Crossfit training

What did the researchers conclude?

The researchers concluded that Crossfit combined with a Paleo style diet is a very effective method to improve endurance, even in very fit individuals. In addition it was also very effective to improve body composition. The effects are comparable with those of studies investigating high intensity interval training. An added advantage is that lean mass improves as well as a result of hypertrophy. However this effect is much less pronounced.

What does this mean for me?

-Crossfit is a very effective method to improve cardiovascular endurance, independent of current fitness level.

-Crossfit is very effective in improving body composition and therefore in improving your figure in a healthy manner.

-Crossfit increases muscle mass as well. However it is less effective than training programs aimed specifically at increasing muscle mass.

See also:

-How to lose weight and fat effectively

-Strength training to lose fat


-Smith, M.M., Sommer, A.J., Starkoff, B.E., Devor, S.T. Crossfit-Based High Intensity Power Training Improves Maximal Aerobic Fitness and Body Composition. Journal of Strength and Conditioning Research 2013, 27, 11, 3159-3172.