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Research Review: Concurrent Training vs. Strength Training Alone

Effect of concurrent endurance and circuit resistance training sequence on muscular strength and power development.

Chtara M, Chaouachi A, Levin GT, Chaouachi M, Chamari K, Amri M, Laursen PB. J Strength Cond Res. 2008 Jul;22(4):1037-45.

Objective: The purpose of this study was to examine the influence of the sequence order of high-intensity endurance training and circuit training on changes in muscular strength and anaerobic power.

Subjects: Forty-eight physical education students (ages, 21.4 +/- 1.3 years) were assigned to 1 of 5 groups: no training controls (C, n = 9), endurance training (E, n = 10), circuit training (S, n = 9), endurance before circuit training in the same session, (E+S, n = 10), and circuit before endurance training in the same session (S+E, n = 10).

Methods: Subjects performed 2 sessions per week for 12 weeks. Resistance-type circuit training targeted strength endurance (weeks 1-6) and explosive strength and power (weeks 7-12). Endurance training sessions included 5 repetitions run at the velocity associated with Vo2max (Vo2max) for a duration equal to 50% of the time to exhaustion at Vo2max; recovery was for an equal period at 60% Vo2max. Maximal strength in the half squat, strength endurance in the 1-leg half squat and hip extension, and explosive strength and power in a 5-jump test and countermovement jump were measured pre- and post-testing.

Results: No significant differences were shown following training between the S+E and E+S groups for all exercise tests. However, both S+E and E+S groups improved less than the S group in 1 repetition maximum (p < 0.01), right and left 1-leg half squat (p < 0.02), 5-jump test (p < 0.01), peak jumping force (p < 0.05), peak jumping power (p < 0.02), and peak jumping height (p < 0.05). The intrasession sequence did not influence the adaptive response of muscular strength and explosive strength and power.

Conclusions: Circuit training alone induced strength and power improvements that were significantly greater than when resistance and endurance training were combined, irrespective of the intrasession sequencing.

Some of my thoughts on how we can use this:

1) There were 4 groups to look at in this study (5 if you count the control group who did nothing, but since they made no improvements, obviously, I will not bother talking about them) and they all had a slightly different sequencing of training over the 12 week block.

The endurance group performed a high intensity interval protocol based around 5 high intensity runs at Vo2max (measured prior to the start of the program. Their rest interval was performed at 60% of their Vo2max and the duration of the sprint interval and the recovery interval were based on one-half of the subjects’ time to exhaustion at their maximal speed (measured prior to the start of the program).

The strength training group performed circuit training workout broken down into 4 three-week blocks. The first two blocks focused on strength endurance and the third and fourth blocks focused on strength and power.

The other two groups performed both training sessions (concurrent training) and the only thing that changed was the sequence of the work completed. So, one group performed the endurance workout followed by the strength workout and the second group performed the strength workout followed by the endurance workout.

2) While the researchers concluded that the strength group out performed the concurrent training groups in strength and power, I thought it was interesting to note that both concurrent groups made similar improvements in strength and power, regardless of whether they performed the endurance training first or the strength training first. I think this is important for a few reasons. First, people seem to always get into the debate of when to perform their aerobic work, “Should I do it after I lift or before I lift?” When we look at athletes who need to perform speed and agility work, it is probably best to perform this stuff BEFORE lifting, as the last thing you want to do is fatigue the lower extremity and then have the athlete go out and try and sprint or do agility work and blow out an ACL or pull a hamstring. I am generally not a big fan of running (more importantly intense running, as used in this study) after a weight training workout. If you are going to perform aerobic work (or sprints) after your weight training and your goal is general health and fitness or fat loss, then I would rather see you hop on the bike, row machine or versa-climber to get the work done as you don’t have to balance yourself and interact with the ground (of the moving ground if you are on a treadmill) and worry about decelerating yourself.

3) This study gives us some good background for planning or periodizing training. As I have said before “You can’t serve too many masters.” Basically what I mean is, it is tough to try and make great improvements in both strength and endurance or speed at the same time. You don’t see powerlifters performing long slow distance running on the weekends and you don’t see marathon runners performing heavy singles and doubles during the week. You have to be specific to what you are training for. Oftentimes people will ask me to look at their workout and it will have some Olympic lifting, some cardio, some heavy strength training and some hypertrophy training all in the same week. Realistically, there is no way they are going to make great improvements in any of those because they are trying to focus on to much. Pick one thing to focus on and attack it. This doesn’t mean that you have to stop doing the other things, but they should make up only a minimal amount of your total training volume (or to paraphrase Zatsiorsky says, “While focusing on one quality, train other qualities at retention loads.” However, in this study the concurrent training group did make improvements, just not as great as training strength alone (if pure strength is your goal, then you should know what to do). Zatsiorsky also says that you should try not to focus on more than two qualities in one training block. This was adhered to in this study as the first phase of training focused on anaerobic endurance (with the sprints) and then strength endurance, followed by the second phase of anaerobic endurance and strength and power. Which leads me to my next point.

4) Going along with our periodization and how we structure our training programs, this study can be helpful as we know that we can make improvements in strength and conditioning (again, not as great as if we only trained strength alone). This can be helpful if we have only a short period of time to work with an athlete (which is obviously not optimal, but does happen). As well, this can help us out in planning as we can focus on our strength and power in earlier phases of training and then as we near the competitive season, begin to transition over to a combination phase (concurrent training) of the qualities need to be successful in the athletes given sport.

5) The fact that similar increases were made in both concurrent training groups can be of some interest to endurance athletes, who in the offseason, may opt to focus on strength and power prior to their endurance work (split into to workouts a day; strength in the AM and run in the PM) and then, as they shift into the competitive season and their marathon prep, they would want to focus mainly on endurance work first (since it is most important at that time) and perform their strength work second in the workout.

6) The subjects in this study were not elite athletes, so it would be difficult to know how the genetically elite would respond. However, there is some good information that everyone can take from this study and apply to their own training program.