A bit later than my usual posting time, but I was out most of the day so I’ve only just finished this!
This was a useful study I stumbled across. I was actually looking for another bench press study, but when I saw this study my interest was piqued. Was this a study I could use as helpful evidence to those women who think that strength training will just get them bulky and therefore turn to yoga believing that greater flexibility equals better health? Could this be a useful study for those of us who train to convince our non-training friends that strength training is not necessarily a bad thing? Read on and find out.
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Influence of moderately intense strength training on flexibility in sedentary young women
Santos E, Rhea M R, Simão R, Dias I, de Salles B F, Novaes J, Leite T, Blair J C, Bunker D J. Journal of Strength and Conditioning Research 2010; 24(11):3144-3149. (Free copy of the study here.)
The study
This study appears to have been trying to consolidate and delve more deeply into a collection of previous studies that had been done looking into the subject of flexibility improvements as a result of strength training. The authors wanted to focus specifically on women in their mid-twenties whereas previous studies had either looked at other age groups or, in one case, had looked at a population of both men and women. In the discussion section of this paper the authors are particularly dismissive of this final study pointing out that not only was there a skew to male participants (65% men and 35% women) but the resistance training group from the study was even more skewed (69% men and 31% women). The authors believe that the influence of strength training on flexibility varies between men and women.
Unlike last week’s study, there are limited subtle comments and side-discussion from the authors of this study, however this doesn’t detract from the helpfulness of the study itself.
The participants
Whereas last week’s study used participants who had been participating in resistance training activities for a minimum of 3-5 days per week for the 6 month period immediately prior to enrolment in the study, this week’s study was looking for young women who had engaged in no physical activity for the 6 months leading up to the study and, in fact, engaged in no regular physical activity other than the study’s strength training programme while the study was taking place. So we move from one extreme to the other – these women are truly sedentary.
Looking at the women selected they all appear to be in their mid-twenties. The test group contained 24 women were divided into three groups of eight and the reported age of each of these groups was 26.8 ± 1.6 years, 24 ± 2.3 years and 25.4 ± 2.4 years.
Before they started the experiment the training groups were put through a week of exercise familiarisation. This seems like an excellent idea as it would have helped prevent the possibility of injury during early training sessions and the initial testing. However, this needs to be remembered when comparing the opening figures between the control group (who were remaining sedentary) and the training groups.
The experiment
The women were divided into three groups. One was a control group and remained sedentary all the time, except when being tested (and presumably for some exercise familiarisation so that they knew how to do the machine bench press for the test). The other two groups were both training groups.
Flexibility and one rep max (1RM) machine bench press were both measured at the start and end of the training period. It’s worth noting that at the start flexibility was measured 48 to 72 hours after the initial 1RM test while at the other end of the experiment the flexibility was measured first, 48 hours after the final training session, and the 1RM was tested 48 hours after the flexibility measurements were taken.
Quite why they decided to swap these round is not certain and the authors say nothing about this. The results are still comparable between the groups as the testing protocol was the same between groups though.
In between the opening and closing testing the training groups did 24 training sessions, three times a week over eight weeks. The training groups did identical workouts except for a different arrangement of the exercises. One group is described as an agonist/antagonist group and the other as an alternated strength training group.
Agonist/antagonist training group
To understand what is going on here it is necessary to understand what agonist and antagonist mean. According to wikipedia, an agonist muscle causes movements to occur through the process of contraction. The antagonist muscle works in conjunction with the agonist muscle, to bring the limb back to its original position. A really good example is the upper arm where the bicep is the agonist when bending the fist up to your forehead while the triceps is then the antagonist, working to bring the arm back to its straight position.
This training group were given the following superset exercises:
- Machine seated row and machine bench press
- Machine triceps extension and machine seated arm curl
- Abdominals and trunk extension machine
- Leg extension and seated leg curl
They completed three sets of each pair, performing 10-12 reps on all except the abdominal exercise which was done for 15-20 reps. The participants took 2 minutes rest between the supersets.
Helpfully they made the workouts progressive, increasing the weight once the participant could complete 12 reps with the weight they were working with.
If you consider the exercises being done by this group the supersets were all made up of pairs of agonist and their matching antagonist muscles, for example the triceps and arm curl which was the example I gave at the start of this section. This is a popular way to train the upper body for a more advanced trainee but for new trainees who have not previously done these exercises it must have been utterly exhausting.
Alternated strength training group
This group did everything exactly the same as the agonist/antagonist group although if my reading of the training protocol is correct then there was only one set done of each pair and the exercises were done in a different superset order. This time they were paired as follows:
- Machine seated row and leg extension
- Machine bench press and seated leg curl
- Machine seated arm curl and abdominals
- Machine triceps extension and trunk extension machine
This is a classic superset of arms with legs, abs or trunk each time – far less exhausting for the beginner trainee as each body part gets a longer rest between sets while the other body part is working.
Results
I have not reproduced the measurements for the six flexibility tests they carried out on the three groups pre and post experiment. The noticeable point is that the control group saw no flexibility improvement while the two training groups both saw improvements in their flexibility. Across the board the alternated strength training group saw greater improvement in their flexibility but by an amount that is fairly immaterial when compared to the overall increase seen by both group. It is therefore fair to agree with the authors when they note that strength training can rapidly improve flexibility in women in their mid-twenties who were previously completely sedentary.
More interesting to me was the results on the machine bench press 1RM. It is important to note that this is machine bench press – free-weights bench press would require far more from the stabilising muscles and would therefore take longer to reach such high numbers. However, the difference between the agonist/antagonist group and the alternated strength training group is he and says a lot for what may be an appropriate way to train a new beginner.
|
|
Pre-training (kg) |
Post 8 weeks training (kg) |
Movement (kg) |
| Agonist/antagonist group |
33.2 ± 5.0 |
40.5 ± 4.8 |
1.4 |
| Alternate strength training group |
29.5 ± 2.9 |
42.0 ± 1.7 |
4.3 |
| Control group |
23.5 ± 2.3 |
24.0 ± 3.0 |
0.2 |
The question becomes, on reading these results, whether you would want to just gain flexibility or become a bit stronger at the same time for no more effort. If the latter is attractive to you (and why would it not be?) then alternate strength training seems to be an appropriate way to go with any previously untrained beginner.
Why the difference in results?
Disappointingly the authors don’t seem to try and address why they think the difference in results came about between the two training groups. I have a couple of theories and have decided to share them below, although I would welcome other people’s thoughts.
Firstly, it is well known that certain leg exercises can give an instant boost to growth hormones. It is possible that interspersing the leg exercises throughout the workout gives a better hormonal response to the upper body exercises. However, the upper body exercises are always done first which potentially detracts from this theory. Perhaps an interesting test would be to replicate this experiment but to have both training groups perform the alternated strength training routine with one group doing the supersets the opposite way round, performing the leg exercise then the upper body exercise, and see if the results differ between these two groups. Would this make any difference? Would it make a difference to the results if the 1RM test being done was a squat rather than a bench press?
Secondly, and more plausible, is the idea that these are beginners. They have, presumably, never done these exercises before, or if they have it was some time ago. As a result those little supporting muscles are not yet very strong. It is likely that the agonist/antagonist workout taxes the muscles much more. While it doesn’t stress the muscles any more, it will stress small supporting muscles that are needed for both exercises in the pair. If they are tired from the first exercise it may not be possible to get the maximum training affect from the second exercise. In comparison the alternated strength training group are giving those smaller muscles longer rest between sets when they want to tax them.
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This wasn’t necessarily the most useful study to improve my own training but I’m hoping that what I’ve learned here will help me convince a few more of my non-training friends that real strength training is not as detrimental to their overall “health” as they may believe. Especially when this could give them some of the flexibility they go to yoga for with a few added enhancements. It’s also given me some good ideas of the sort of workout I might prescribe to a new beginner, although perhaps with a bit more free-weights work and a bit less machine use! Do you think you can similarly draw on this study in your own training or in convincing friends to take it up?
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A very prolific week of links… « Sceptically Fit // Jan 22, 2012 at 21:40
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