Exercise as it relates to Disease/What are the adaptations of strength training with blood flow restriction in women with osteoporosis?

This page is a critique of the research article of: Silva, J., Rodrigues Neto, G., Freitas, E., Neto, E., Batista, G., Torres, M., & do Socorro Sousa, M. (2015). Chronic Effect of Strength Training with Blood Flow Restriction on Muscular Strength among Women with Osteoporosis. Official Research Journal of the American Society of Exercise Physiologists, 18(4), 33-41.

Contents

 * 1 What is the background to this research?
 * 2 Where is the research from?
 * 3 What kind of research was this?
 * 4 What did the research involve?
 * 5 What were the basic results?
 * 6 What conclusions can we take from this research?
 * 7 Practical advice
 * 8 Further information/resources
 * 9 References

Background
Strength training has been identified as both a preventative measure for the onset of osteoporosis, and for increasing bone strength and slowing down the rate of degeneration of bone mass with those already diagnosed. Resistance exercise will induce osteogenesis, and inhibit bone reabsorption, strengthening bones. It will also increase mobility and balance, reducing the risk of falling.

Blood flow restriction training (BFR), or occlusion training, is a training method where the muscles being worked have a disrupted blood flow. It can induce increased muscular strength and hypertrophy at a very low intensity (20% 1RM). Training without blood flow restriction at this low intensity is ineffective.

This study focuses on older women with osteoporosis, and determining if it is an effective regime for this population for increasing strength. The results for this study will be insightful from a clinical perspective, as many may not be able to physically handle heavier loads that would normally be required for strength and hypertrophy progressions.

Where is the research from?
This study was published 2015, with the authors from the Federal University of Paraíba, and the State University of Rio de Janeiro. The authors of the article appear to be reputable and experienced, with the authors to date having been apart of 195 publications. It's important to note that Brazil is a developing country, so the incidence and severity of osteoporosis may vary from that of a developed country.

The funding of this study appears to come from the universities. There does not appear to be any obvious or concerning conflict of interest or bias from any authors or parties involved.

What kind of research was this?
This study was executed as a randomised control trial. A randomised control trial is best for this study, being the gold standard in assessing potential new interventions. The randomised allocation of the participants cancels out potential biases, and differences in the results can be attributed to the intervention itself. Other study designs may lack this, as it could not be determined if a confounding variable influenced the outcomes.

What did the research involve?
There were a total of 15 participants. The participants were women over 50 years of age, had spent at least 6 months without performing any lower body strength training, and were diagnosed with osteoperosis with a t-score lower than -2.5 standard deviations. The strength training program lasted 12 weeks. The control group were to go about their normal lifestyle with no strenuous activity of the lower limbs. The intervention groups trained twice per week, with a unilateral leg extension as the exercise being tested. The high intensity group did 4 sets until concentric failure, at 80% 1RM. The BFR group were fitted with a blood pressure cuff at a mean pressure of 104 Hg, and a vascular doppler placed on the tibial artery of the right leg. They then performed 4 sets until concentric failure at 30% 1RM.

1RM testing was conducted before initiation of the program, in the sixth week, and in the 12th week, with the maximum strength of the right lower limb being tested.

The study could have gone into more depth by testing several unilateral and bilateral exercises targeting different movements. If the results in this study show a positive adaptation to the intervention, it is only localised to the right lower limb, and whether this intervention is useful for other limbs remains to be seen. This is important as osteoporosis affects many structures, such as the spine, humerus and the wrist.

The population of the study was very small. The participants were all in Brazil, and likely confined to an area close to the researchers for convenience of recruitment. This means that the results of the study may not be a valid to a wider population as there was not enough participation nor variety in the demographics.

The discrepancy in body mass with the group training with blood flow restriction is undesirable. However, due to the low number of participants and substantial standard deviation, this may be irrelevant.

Results



 * Strength is increased gradually by a high intensity program, as well as a lower intensity BFR program.


 * The control group showed no improvement.
 * High intensity training was the best method in increasing strength, being slightly more effective than the BFR method.


 * The researchers concluded that a low intensity regime with BFR is a viable alternative for a clinical population who may find it difficult to train.


 * The researchers acknowledged the small impact of their study due to sample size, and have encouraged further studies on an elderly osteoporotic population.
 * They have exuded confidence, emphasising previous studies into strength training with BFR in healthy populations which correlated with the results.

Conclusions

 * More evidence is required. Further replications of this study will ensure the findings are reliable.


 * The small sample size may render this study invalid, so further study is critical.


 * The discrepancy in the weight lifted in the BFR group in the pre test is concerning, considering it was a randomised control trial.


 * This may mean that the strength increases with this intervention may be inaccurate in a larger population, and will need to be confirmed with further studies.


 * It is reassuring that these findings line up with those of other studies. A meta analysis on low intensity BFR training found it was an effective way to increase muscular hypertrophy, strength, and eventually neural adaptations.
 * Evidence suggests that initial increases in strength is solely due to muscular hypertrophy, with neural adaptations occuring later, which is an opposite trend compared to traditional strength training.

Practical advice

 * BFR training is safe in healthy populations, but more research is required before it can be widespread in a clinical setting.
 * May be a useful tool to induce hypertrophy and strength at lower intensity in a clinical population.


 * If you suffer from osteoporosis, the best way at present to build muscle strength and size is to follow a traditional high intensity program.
 * A BFR program will provide similar adaptations with reduced mechanical stress and should be encouraged if a client cannot cope with heavy loads.
 * A full body program should be implemented, as adaptations are highly specified to what part of the body you are training.


 * Make sure your program is specialised, as osteoporosis will present limitations to completing a normal strength training program.
 * High volume is preferable.

Further information

 * Osteoporosis: https://www.aihw.gov.au/reports/chronic-musculoskeletal-conditions/osteoporosis/contents/what-is-osteoporosis
 * Blood occlusion training: https://www.healthline.com/health/fitness-exercise/occlusion-training


 * https://healthybonesaustralia.org.au
 * Contact an orthopaedic surgeon for an assessment.