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Concurrent training: how to simultaneously train upper and lower body strength, muscular endurance and flexibility
Research suggests that concurrent training can train several aspects of fitness at once
Many sports require high levels of upper and lower body strength, muscular endurance and flexibility, yet the prevailing wisdom is that you can’t train all these aspects of fitness simultaneously. However, according to James Marshall, new research suggests that concurrent training can deliver the goods
Prevailing wisdom says that by training on one area you automatically interfere with the development of another. In this article, we’ll look at recent research from the University of California that shows how a method of training (previously covered in PP 247) can improve all these factors at once (1,2).
Explosive movements require a strength base, while throwing, striking and hitting actions also require strength. Players who are leaner have less weight to carry around and so (all other things being equal) experience less fatigue. Players who have a greater VO2max (maximum oxygen uptake capacity) can recover more quickly between these repeated bouts of work.
Rarely does a sportsman or woman use either strength or endurance in isolation; if you become stronger, but can’t do as much overall work because you have poor endurance, you will be less effective. Conversely if you run around and get to a lot of positions but can’t then execute effectively because you’re too weak, that’s no good either!
Given the above, it makes sense that training for a particular sport should (at least some of the time) reflect the demands of that sport and that means working on endurance, strength, and muscular endurance at the same time. Concurrent training is the integration of aerobic type work and resistance type work in the same session. This is a very time-efficient method of training, allowing a lot of activity in different formats to be performed in a short space of time.
Coaches have known this for a long time; go to most combat sport gyms and you will see fighters working on bags, followed by circuit type exercises, followed by sparring or combinations of all three. Rugby League players often play small games, which require running around, followed by some partner resistance work or tackling bags or getting up and down off the floor, followed by more games.
However, some research has shown that trying to work on strength and endurance concurrently can interfere with muscle power or strength adaptations (3). This is also commonly stated in physiology textbooks and so sports science undergraduates are taught this, too (4). This leads to a situation where coaches who are training athletes see results, but sports scientists who are measuring physiological parameters come up with different answers from the coaches.
Whether you think the coach or scientist is right can depend on the research that you look at. The nature of research and publishing normally means that you have to look at one specific area, test it, apply a training principle and then retest it. In order to eliminate all other variables, researchers often limit their study to one specific area, and study that in detail (see box 2). Unfortunately this approach doesn’t always transfer to the real world because the body (and the athlete) may not respond the same way to events and stimuli in isolation. Most athletes have to work on technical and tactical aspects of their sport for most of the year. Many of these sessions will be having at least some conditioning effect, so one aspect of training cannot be isolated.
Another possible reason why some studies have found concurrent training ineffective is that they were conducted without following periodised plans, which may have led to overtraining. The study by Hickson consisted of ten weeks’ continuous progressive exercise, with strength lessening in the last two weeks (9). If an athlete starts a programme with residual fatigue, he or she will not be able to adapt to an increase in stimulus and instead suffer a drop in performance, or a plateau.
Meanwhile, some studies looking at concurrent training and which showed interference (ie concurrent training ineffective) used untrained subjects (10,11). The studies that have shown no interference and improved both endurance and strength have used well trained subjects (12,13,14). It may well be, therefore, that untrained subjects do not have the capability to adapt to the combined training load.
Also, a lot of the research has looked at concurrent training where strength and endurance work were performed in different sessions in the same week or where basic concepts of periodisation weren’t applied. One of the first studies looking at concurrent training was by Hickson, back in 1980(9). The study used three groups of subjects:
An endurance group, who alternated between interval training using six 5-minute sets with 2 minutes’ rest on a cycle ergometer three days a week, and a running programme of 30 minutes in week one, 35 minutes in week 2 and 40 minutes thereafter;
A strength group who trained three days a week on five sets of 5 parallel squats, with three sets of 5 reps on knee extensions and knee flexions; and two days a week on three sets of 5 reps on leg press and three sets of 20 reps on calf raises, with additional deadlifts and sit ups;
A combined group who did both training protocols with a 2-hour rest between the endurance and strength sessions.
The results were as follows:The endurance group improved their endurance with no change in strength;
The strength group improved their strength with no change in endurance;
The combined group improved their endurance as much as the endurance-only group and also, for the first seven weeks, their strength. The strength gains leveled off, however, between the 7th and 8th weeks and then decreased during the 9th and 10th weeks of training.
This last result is not surprising; the subjects had not done any training for months prior to the study and it’s likely they adapted for seven weeks and then predictably got tired. If the study had stopped at eight weeks, the combined group would have shown gains in both strength and endurance. After ten weeks of continuous training, it’s possible that the subjects were overreaching (see box 2), especially at the loads and intensities set. Yet this study is often cited as ‘proof’ that concurrent training limits strength adaptations.
Researchers in California recognised these problems and designed two comprehensive studies that utilised concurrent training within the same session and measured several performance outcomes (1,2). The first study used 28 female soccer and volleyball college athletes as subjects and measured the following:
1 repetition maximum (1RM) of three lower body and five upper body exercises;
Muscular endurance of the legs using leg press and upper body on five different exercises;
Body fat percentage and fat free mass;
Upper and lower body flexibility.
The second study used the same female athletes and also 20 male athletes and measured systolic and diastolic blood pressure and VO2max on a graded treadmill running test. Both studies were conducted over 11 weeks with the subjects training three times a week for an hour and 50 minutes each session. The subjects were split into two groups who performed the following:
Serial training group
Aerobic warm up – five minutes;
Alternating sets of resistance exercise with brief rest periods – 60 minutes;
Aerobic exercise – 30 minutes;
Range of motion cool down – 15 minutes;
Integral training group
Aerobic warm up – 20 minutes;
Alternating sets of resistance exercise with brief aerobic cardioacceleration – 75 minutes;
Range of motion cool down – 15 minutes.
In the resistance section of the workout, both groups did three sets of 8-12 repetitions of nine different exercises, starting with a load of 50%1RM. The difference was that in the serial group the heart rate was deliberately kept low (107.9bpm) by sitting down between sets whereas the integrated group performed 30-60 seconds of vigorous aerobic exercise (usually treadmill running) to elevate their heart rate (151.1bpm) between sets. The serial group performed their aerobic exercise after their resistance training. Both groups did exactly the same amount of work; it was just the sequencing of the exercises that was different. Both groups then finished their workout with 15 minutes of range of motion exercises.
There were three hypotheses in this study:
1. Serial training is as effective as training in either strength or endurance alone, producing similar gains;
2. Integrated training produces training effects that are greater than single mode training alone;
3. Integrated training produces greater training effects than serial concurrent training.
The results (see table 1) showed that all three hypotheses were correct (the authors did not have controlgroups who performed the single mode of exercise alone; instead they compared their results with those produced from other studies that did only use single modes of exercise). The two main points here are that there was no apparent interference effect from combining strength and endurance training; and that simply changing the sequencing of exercises can have a very big impact on results. In fact, apart from the upper body strength and muscular endurance, all parameters measured in the study were improved more in the integrated than serial group.
The authors of the Californian study above suggested that in integrated training there is actually a synergy between strength and resistance training, and the results seem to support this. It could be that by elevating the heart rate and increasing blood flow to the muscles prior to strength training, the movement of hormones such as insulin and nutrient delivery to muscles is enhanced, leading to greater recovery and adaptation. This same mechanism also assists in delivery of oxygen and removal of waste products, which would assist local muscular endurance.
Integrated training may also help the heart (which is of course a muscle itself) become stronger and more efficient by repeatedly challenging the vascular pump within the heart and by increasing muscle perfusion within the cardiac muscle. This repeated stimulus may be a better way of working the heart muscle than a single block of aerobic work after the resistance training.
Taking information from one study and trying to apply it wholesale isn’t always wise. For starters, an hour and 50 minutes (as used above) is a long time to work out. In my experience an hour is pretty much the longest you can train while still maintaining intensity and concentration. Also, the subjects in this study were not playing any sport at the time, which means they didn’t have to do technical/tactical sessions, play matches or to nurse the bumps and bruises associated with competition!
Having said that, there are some important take-home points. Firstly, the sequencing of the exercises does seem to have a major impact on the results, even when the same amount of work is performed, and integrated training appears more effective than serial training. This means preceding weight-training sets with a brief period of 30-60 seconds of aerobic work throughout the session.
Secondly, the concept of hard/easy days isn’t new and allows recovery of glycogen and adequate protein synthesis to take place. This could be the key difference between this study and others (which did not provide adequate recovery for their subjects) that showed an interference effect, and should be a principle in your training, too.
Thirdly, studies that have shown an interference effect have been conducted on untrained subjects, so if you are new to training, or returning from injury, it may be best to separate the two modes of training first – ie perform serial rather than integrated training. However, if you are well conditioned, then integrated sessions could be for you, as long as you allow adequate recovery between your sessions.
James Marshall MSc, CSCS, ACSM/HFI, runs Excelsior, a sports training company
1. Journal of Strength and Conditioning Research, 22(5), p1487-1502, (2008)
2. JSCR 22(5), p1503-1514 (2008))
3. European Journal of Applied Physiology, 92, p376-384 (2004)
4. Essentials of Exercise Physiology, p494. MCKardle, Katch and Katch, Philadelphia: Lippincott Williams and Wilkins (2006)
5. Annual Review of Nutrition 20, p 457:483 (2000)
6. Eur. J. Appl. Physiol. 89:42–52, (2003).
7. Journal of Applied Physiology. 99:950–956, 2005
8. Journal of Applied Sports Science Research. 4:55–60, 1990
9. European Journal of Applied Physiology 45, p255-263 (1980)
10. Eur. J. Appl. Physio 92, p376-384 (2004)
11. Medicine and Science In Sports and Exercise, 348-356 (1990)
12. JSCR 15, p172-177 (2001)
13. JSCR 20, p541-546 (2006)
14. JSCR 17 p393-401 (2003)