Ask anyone who has pulled a muscle and they will tell you the importance of flexibility. Flexibility can be defined as the ability to move a joint though its full range of motion. Good flexibility is important for normal movement and injury prevention. Flexible hip and thoracic spine (upper back) joints help maintain spinal alignment and proper posture. Flexible ankles and shoulders help reduce stress on the knee and neck region. There is even evidence that poor flexibility may impair the ability to increase strength with resistance training. There is a prevailing idea that resistance training will decrease flexibility and trainees should be careful of becoming “muscle bound,” and there is some scientific evidence to support this belief. A study done in 1995, published in Medicine & Science in Sports & Exercise, tested 31 untrained men between the ages of 50 and 74 to compare the effects of strength with flexibility training, flexibility only training, and no training (inactive control group) on shoulder and hip range of motion. The researchers found that, “The results indicate that the flexibility group increased its range of motion in shoulder to a significantly greater extent than the strength training and flexibility group.” The key idea coming from the study was that strength training reduced the flexibility training improvements. The “muscle bound” idea is also exacerbated by many young muscular males that have poor flexibility. This has all helped lead to the long held idea that weight training decreases flexibility. However, is this really the case? In a recent study, Resistance Training vs. Static Stretching: Effects on Flexibility and Strength, published in the Journal of Strength and Conditioning Research found evidence that strength training can increase flexibility. After five weeks of either flexibility training or strength training, both groups increased their flexibility over the control group. Strength training increased flexibility instead of decreasing it. The researchers stated that, “the results of the study suggest that resistance training — so long as it is done over that appropriate full range of motion — will have positive benefits on flexibility.”The problem isn’t with resistance training, it is with the inadequate range of motion most lifters use when performing their resistance training exercises. Many recreational weight lifters tend to sacrifice range of motion for weight. Going too heavy and not going completely thorough the joints full range of motion. The same mistake may explain why the older adults in the first study didn’t increase their flexibility. They may not have trained through the full range of motion, as many untrained trainees seldom do. This is why proper form and a balanced weight training program are paramount. The best training option is to include both resistance training through a full range of motion and stretching to help improve and maintain flexibility. —Kyler Crouse, BS, CSCS, FMS is a personal fitness coach that works out of Sierra Athletic Club and in the homes of clients in the greater Lake Tahoe area. Please visit www.KCstrength.com for more information and articles.