Monday, January 17, 2011

Is Weight Training Alone Enough to Increase Flexibility?

The main reason given by women for avoiding weight training is that they do not want to become big and bulky, or in other words, “masculine”. I plan to address this misnomer more thoroughly in another post. For now, I’ll just say that this is not true, largely due to the fact that women generally do not have the needed Testosterone to become overly muscular. However, I will digress and on move on to the issue at hand. Is weight training alone enough to induce flexibility gains?  This article is more geared towards women for two reasons; 1) they tend to engage in weight training less than men & 2 a lot of the available research on the issue is geared towards women.
                A recent study by Elisa Santos and colleagues found that performing a moderate strength training protocol is enough to elicit flexibility gains in previously sedentary young women (mid to late twenties) (1). The researchers divided subjects into three groups. There was a control group and two groups who performed resistance training 3 x a week for 8 weeks. Furthermore the resistance training groups were divided into 2 groups, with one group performing a more traditional style of lifting and the other performing a regimen similar to circuit training. The set/rep scheme was 3 x 10-12 except for the abdominal exercise which was 3 x 15-20. There are few “interesting” things about this studies’ methodology to be taken into consideration;
                1) The exercise selection was not exactly optimal in that none of the movements involved the use of free weights or even body weight variations of compound movements. The exercises prescribed were in this order: machine seated rows, leg extension, machine bench press, seated leg curl, machine seated arm curl, abdominals (curl ups), machine triceps extension, and trunk extension machine.  
*This basically means the ladies just sat at machines to perform the exercises rather than getting up and performing skilled movement. It’s fine for beginners but does not translate as well into real world movement efficacy.
2) The circuit training group performed the exercises in an agonist/antagonist fashion with no rest between sets.
                                On completing 3 sets of one exercise pairing, subjects rested 2 minutes before proceeding to the next exercise pairing”
**I have never seen a protocol quite like this and I believe performing the same 2 exercises back to back to back with no rest is not conducive to facilitating movement skill, but simply fatigue. Doing this with several varied exercises and then repeating after rest is more practical.
3) The flexibility measures did not include the lower body. The only joints included were the shoulder (extension, flexion, adduction, abduction) and the trunk (flexion & extension)

Despite these peculiarities, the researchers found that both groups participating in resistance training improved both indicators of strength and improved flexibility. Previous studies have also found that resistance training improves flexibility in some but not all joints involved in the resistance training protocol. (2) In this trial, using “middle aged women” (35-39 yrs) flexibility was also measured at the hip, knee, and elbow in addition to the joints in the previous study. The elbow and knee joints were unaffected. The protocol while much improved was not optimal. The following exercises were used free-weight flat bench press, smith machine squat, anterior wide grip lat pull-down, 45-degree leg press, 30-degree inclined bench press , hack squat machine, and abdominal crunch. Personally I would like to ditch some of the machines and include more free weight movements such as dead lift and lunges, maybe even a progression to a split squat to really force range of motion, proprioception and neural drive.

                To put these findings into context, one might infer that resistance training is advantageous for not only strength and muscular endurance, but flexibility. And luckily there is more data in addition to the studies elucidated on here to support this (3, 4, 5). There has been research that did not find improved flexibility following weight training but flexibility was not lost and as with the previous study programming was far from optimal (6). I think it is safe to say that whether you are a women concerned with not becoming bulky or a female athlete or coach concerned about strength training diminishing flexibility, you can rest easy and hit the weights knowing at the very least you will not do so, and you may perhaps gain flexibility through weight training and/or use it to augment the results of a flexibility training regimen.
Iris Kyle, Ms. Olympia...Sorry Iris but most women are not shooting for this physique :(

1) Santos E, Rhea MR, Simão R, et al. 2010 Influence of moderately intense strength training on flexibility in sedentary young women. J Strength Cond Res. 24(11):3144-9.
2) Monteiro WD, Simão R, Polito MD, et al 2008 Influence of strength training on adult women's flexibility. J Strength Cond Res. 22(3):672-7.
3) Thrash K, & Kelly B. 1987 Flexibility and Strength Training. J Strength Cond Res. 1(4): 74-75
4) Beedl B, Jessee C,  & Stone M. 1991 Flexibility characteristics among athletes who weight train. J Strength Cond Res. 5(3):150-154
5) Bird ML, Hill K, Ball M, & Williams AD. 2009 Effects of resistance- and flexibility-exercise interventions on balance and related measures in older adults. J Aging Phys Act. Oct;17(4):444-54.
6) Nóbrega AC, Paula KC, & Carvalho AC. 2005 Interaction between resistance training and flexibility training in healthy young adults. J Strength Cond Res. 19(4):842-6

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