Injury and resistance training

[Belle]

http://www.discoverfitness.com/Resea..._Strength.html

The Effects of Strength Training and Detraining on the Bones of Healthy Young Women*

The benefits of resistance training are well known. An increase in Bone Mineral Density (BMD) and Bone Mineral Content (BMC), and an increase in muscular strength are two of the more important benefits. Increasing and maintaining BMD and BMC is important to maintain bone integrity and health and help prevent osteoporosis. Vuori et al. looked at the effect of one year of high intensity resistance training on muscular strength and BMD and BMC. This was followed by looking at the effects of three months of detraining on the same variables.

12 females (average age of 21 years old) participated in this study. The training protocol involved doing the leg press 5 days a week using only their left leg. (This was done to see the effects of training one leg versus the other leg). The participants performed 5 sets of 10 repetitions at a high intensity.

Results:

After 12 months of exercising:

Muscular strength: In the trained leg, muscular strength increased by 26% and it increased by 16% in the untrained leg.

BMD: Increased in the lumber spine by 2%

Increased in the femoral neck by 1.1% (The upper portion of the femur)

Increased in the distal femur by 2.0% (The lower portion of the femur)

Increased in the patella by 1.6% (The knee bone)

Increased in the proximal tibia by 2.2% (Upper portion of the lower leg)

Increased in the calcaneous by 2.0% (The heel)

BMC: Increased by an average of 2.7%.

After 3 months of detraining:

Muscular strength: Remained virtually unchanged.

BMD: The values all decreased to the baseline values (the values before the training began).

BMC: Decreased steeply in both legs.

What does it all mean?

This study shows us that performing resistance training can help increase muscular strength and can help make your bones stronger. This will help you reduce the likelihood of osteoporosis later in life. This study also shows that there is a cross-training effect of exercising. If you perform resistance training with one arm, you will increase the strength in the other arm. This is useful for when you injure a body part. If you exercise the uninjured limb, you will be able to maintain or decrease the loss of strength in the injured limb. Lastly, and perhaps most importantly, this study shows us that if we do not continue to perform resistance training, the benefits to our bones will not remain. This is why it is so essential to make exercise, including resistance training, a regular part of your life. Your bones will thank you later. For more information on resistance training, please see the following sections in http://www.discoverfitness.com -(1)How to Get Started/Designing a Program and (2)How to Organize Your Resistance Training Routine, or write to the Fitmaster at Fitmaster@Discoverfitness.com.

*The information for this section was provided by Vuori, Heinonen, Sievanen, Pasanen and Oja, from the article entitled, Effects of Unilateral Strength Training and Detraining on Bone Mineral Density and Content in Young Women: A Study of Mechanical Loading and Unloading on Human Bones, from Calcification Tissue International, Vol. 55, 1994.

Disclaimer: The information provided by this service is intended to serve as recommendations for people who desire to learn more about health, fitness, and taking care of their bodies. Before beginning any exercise program, always consult your doctor to make sure you are able to begin exercising. Certain disabilities or conditions may contraindicate some activities, so be sure to clear yourself with your doctor.

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Does this mean that if I just do resistance training in my unaffected leg, that it will naturally increase the strength in the other leg? If this is true I think leg day will be different.

[TrishB]

I would not put much faith in, or pay much attention to any study that only involved 12 people.

[TwoWalks]

Originally posted by Belle
[url] involved doing the leg press 5 days a week using only their left leg.

Muscular strength: In the trained leg, muscular strength increased by 26% and it increased by 16% in the untrained leg.

Ever done a heavy resistance leg workout and then walked really funny for a couple of days? I would bet the answer is yes. Now think about that same pain being in one leg only, you would transfer most of your own weight to the other leg while walking, result an increase in the strength of the other leg.

As far as the chemical increase that improved the bone structure ... this would be created in the body and transported to all the bones within the body so again not surprised even if only using one leg.

One should not transfer this thinking in a manner to believe that exercising one arm will cause the other to increase in strength unless the other arm is then used in a different manner to take up the slack for the arm that was worked. To gain strength the muscle has to experience an increased load at some point.

[MiloMan]

Some of the best studies re: the effect of stress loading (and reduced stress loading) on bone density were done by NASA; hunt them up if you have the time.

[Belle]

With an increase in dhea in your body due to strength training in general, even though you only worked one leg the, bone density would increase throughout both, not just in the leg that you worked out. This is the effect of increased dhea on bone and why they recommend resitance training for those predipsosed to osteoarthiritis. That was the gyst of what I gleaned from this study anyway which basically would make sense to me. Your theory around the increase in strength of the muscle in the other leg also makes sense too Two Walks. I'd obviously have to make sure I am not going so hard I am limping around on the right leg too much. I thought to do it to increase the bone density in both due to the knee problem--joints/bones etc.

The study from what I could gather was testing bone density as well as the muscle strength increase and they would have used high tech scanners to check the bone density of each leg I guess. I have would tend to believe that it is accurate for that reason. Even if it were only 11 people involved when you think about it it is just too much of a coincidence for them all to have had such a vast increase in bone density from one leg to the other leg following that exercise regime. Well that's my take anyway. If I exercise my left leg more, it is only going to end up as used as my right leg given that the right leg was stronger and slimmer, maybe doing that will even out things anyway as well as helping the bone density and muscle strength. I'll just have to keep my tape measure handy to check things arn't getting too out of shape and obviously larger. Seems like the best thing to do at the moment anyway until my other leg heals properly.

[Hibiscus09]

originally posted by TwoWalks
Ever done a heavy resistance leg workout and then walked really funny for a couple of days?

You should have seen the way I was walking this weekend!