Saturday, January 8, 2011

Is body weight training adequate to attain a high level of fitness?

                I’m snowed in today so I decided to skim through some back issues of the NSCA’s Strength and Conditioning Research Journal. I came across an interesting study done by Everett A. Harman and colleagues at the U.S. Army Research Institute (1). The study compared the effects of eight weeks of  a resistance training-based training program  in contrast to the Army Standardized Physical Training program. The Army program is essentially a regimen based off body weight resistance.  My interest was piqued by the fact that the researchers used these protocols to attain the effects they had on combat relevant tests, as well as other more common tests used to asses physical fitness, including the one repletion max (1RM) bench press and squat test and the Treadmill VO2* max test as well. These tests are very relevant to the average person in combat tests are about as “functional” as you can get. Performing this battery of tests at a high level more than ensures that one could perform the pertinent tasks of civilian life with ease. With that said, I thought it would be interesting to see if body weight training alone was enough to attain adequate strength levels.

The researchers found that for, the Army's Standardized Physical Training program and a weight-based training experimental program produce similar, improvements in military physical performance. However, I have to note that these were relatively untrained men and the programs were only followed for 8 weeks. The authors do conclude that further research would be needed to determine whether weight-based training provides an advantage over a longer training period (which I am sure it would). The principle of progressive overload leads me (as well as the authors) to speculate that the weight based program would have won out in the long term. However, the findings of this study do have relevance for the lay man and women when one reads the study closely. Let me elaborate.
The subjects included in this study were in relatively decent shape to begin with. In order to simulate a recruit population, only volunteers who were not currently or recently engaged in intense training (a combination of aerobic and weight-based training) were accepted. However individuals engaged in aerobic only, resistance training only, or moderate recreational exercise were allowed. The subject population was decently heterogeneous, with volunteers coming from varied backgrounds. Their physical activity levels ranged from sedentary to fairly active (training 3-4 x week). With that said I am speculating that the training adaptations by these individuals would only be magnified in the general population in the U.S. The last I heard the CDC was reporting only 34.7% of the pop. was exercising and that was an improvement over previous years. (see here)

 The subjects all volunteered for this training which consisted of 5 days of training per week at 1 to 1.5 hours per session. The subjects were in the upper 20’s and average weight of the subjects was 84.5 kg (174lb) for Army Training group and 80.9kg (165lb) for the weight based resistance training group. With that said, one can assume that no couch potatoes would have signed up for this, and if they did, they probably quit (10 of the original 42 subjects dropped out of the study).
If the training got relatively fit subject into shape, imagine the gains that could be made by this guy!

Training for the weight based group included 2 days of resistance training coupled with 3.2 km (2 mile) runs, 2 days of athletic enhancement via agility drills or sprint intervals, and 1 day that included an 8 km (roughly 5 miles) hike with a weighted vest or pack up to 33 kg (73lbs) at a pace of a little under 4 mph. The resistance training protocol consisted of 4 complexes* to be repeated 3 times each. The 4 complexes summed to put together a full body workout. There was no waiting time between exercises beyond what it took to walk between stations and set the correct weight. The target pace was 90 seconds per set, including between-exercise time. In other words, the trainees were training circuit style.
The subjects performing the Army’s standardized protocol used movements such as the pull up, push up, rear lunges, etc for their resistance training. They also performed aerobic conditioning similar to the weight based training group, doing intervals, moderate distance runs, etc. The exact training can be seen in the IET Standardized Physical Training Guide here or in the full text version of the study.
The five combat relevant tests the authors chose were the 3.2 km run/walk with a 32 kg (70 lb) pack, a 400 m run with an 18 kg (40 lb) load, an obstacle course, and an 80 kg (176 lb) casualty recovery drill, and 30 meter rushes (basically a sprint test). As stated earlier, subjects also performed pre and post testing of the VO2 max and 1RM max testing of the squat and bench. In all of the tests mentioned, both groups made statistically significant improvements from pre test to post test (p < .05). Interestingly, the relative gains made by the Army’s body weight training group was significantly greater than the group using the weight based program in the obstacle course, the 80 kg (176 lb) casualty recovery drill, and 30 meter rushes.  Now let’s put this in to perspective

The resistance training undertaken was not traditional resistance training. The loads used were not what would be considered heavy due to the fast pace and high total volume (volume was high because the workouts were full body) The authors also had to put together a program that coincided with heavy aerobic training and being that the sessions were full body, volume for individual body parts was inherently low. Again, it should be reiterated that  the subjects were already in decent shape. The average VO2 of the subjects were close to 50 mL·kg-1·min-1   to begin with. This would place them in about the 70th percentile (normative chart here). The degree of improvement one can expect in VO2max generally depends on the pre training level, and fit volunteers generally show relatively small percentage changes. Again these volunteers were relatively fit, so most individuals would see an even larger gain on similar programs.
                In conclusion, we have to consider that some of these individuals had already been participating in resistance training, yet the body weight training of the Army's Standardized Physical Training program was still enough of a stimulus to elicit training adaptations in the bench press and the squat, two of the main movements in resistance training. Individuals who find body weight too challenging could begin by using hold and negatives or partner assisted concentric and work their way up. The findings of these study reveal that while body weight training may not turn an individual into the next Mr. or Mrs. Universe, it will reap the awards of increased muscular strength and endurance (sit up and push up testing was also performed). Further research should be conducted using body weight training in conjunction with some conditioning to monitor the changes that could be witnessed in the lay man or lay woman or diseased population, which are unfortunately becoming more and more “normal”. One of the major reasons public health officials list for the obesity problem in our country is lack of equipment/resources due to poverty. Simple body weight programs seem to be enough of a stimulus to get people into “fighting” shape.

Harman, E Gutekunst, D Frykman, P Nindl, B Alemany, J Mello, R & Sharp, M. (2008) Effects of two different eight-week training programs on militaryPhysical Performance. Journal of Strength and Conditioning Research. 22(2):524-534

*For everyone unfamiliar, the VO2 max test is just a test that measures the aerobic fitness of an individual by determining the theoretical maximum amount of oxygen they could use in a minute.

*A complex consists of performing a series of 3-5 exercises consecutively before taking a rest period and then repeating this complex for a predetermined number of sets.  The protocol in the study essentially had the participants performing multiple complexes, so the training was probably pretty tough!

1 comment:

  1. This is not surprising because Interesting article and one which should be more widely known about in my view. Thanks! Beginner weight training for women