The physiological differences, particularly the influence of hormones like estrogen, play a significant role in how women respond to exercise and their susceptibility to certain injuries. This blog post aims to provide an evidence-based overview of these considerations, helping women optimise their training while minimising the risk of injury.
The Role of Estrogen
Estrogen is a key hormone that significantly impacts various aspects of a woman’s physiology, including bone health, muscle function, and injury risk.
Bone Health
Estrogen is vital for maintaining bone density as it promotes bone formation by stimulating osteoblast activity and inhibiting apoptosis (cell death), while simultaneously reducing bone resorption by suppressing osteoclast formation and activity and inducing osteoclast apoptosis.
Let’s break it down.
What are osteoblasts? They’re cells responsible for bone formation and mineralisation, with strengthens the bone matrix leading to greater bone density. Estrogen also inhibits the death of these cells. Extending their life span to lay down more bone.
What are osteoclasts? They’re cells responsible for bone resorption, a process essential to maintain calcium homeostasis. Estrogen inhibits/suppresses osteoclasts and promotes apoptosis in osteoclasts thereby reducing bone resorption.
This delicate balance maintained by estrogen is crucial for maintaining bone density and overall bone health. The decline in estrogen levels during menopause is a significant factor in the increased risk of osteoporosis and fractures in post-menopausal women. This can be minimised with resistance training. The body is very smart and adaptable, it will lay down new bone in response to load. With weight training, running, and impact exercises, the bone is stressed, stimulating bone formation and increasing bone mineral density.
How much weight do I need to lift? As long as the amount of force resisted exceeds the amount of force an individual typically encounters in everyday life, bone formation will be stimulated to meet the higher physical demands.
We recommend resistance training at any age! Earlier is better for bone health and to lay a solid foundation of bone mineral density whilst estrogen levels are higher. However, it is never too late to start even at 65 years old and above.
During the menstrual cycle, estrogen levels fluctuate, affecting bone resorption and formation. High estrogen levels, such as those during the follicular phase of the menstrual cycle, are associated with increased bone formation. If there’s a heavy/intense training session scheduled for your week, it’ll be beneficial to time it with the follicular phase for maximum benefits.
Injury Risk & Prevention.
Women are more susceptible to certain injuries, such as anterior cruciate ligament (ACL) tears, particularly due to hormonal influences and anatomical differences.
Estrogen decreases stiffness in tendons and ligaments, which directly affects performance and injury rates. Estrogen inhibits lysyl oxidase, an essential enzyme involved in the cross-linking of collagen and elastin. These are the two primary components in ligaments and tendons, which give them their stiffness and strength. As a result, females are 2-8 times more likely to experience ACL ruptures compared to males.
As the reduced stiffness in tendons and ligaments is a natural result of higher estrogen levels, injuries can be reduced and prevented with neuromuscular training and strength programs. Neuromuscular programs should focus on balance, strength, agility with good motor control, to prevent stresses on certain ligaments and tendons. Strength exercises for ACL prevention should focus on overall lower limb strength especially hamstring and quadriceps strength, to maintain joint stability.
By understanding the unique physiological aspects of women, especially with the role of estrogen on bone health and connective tissue stiffness, women can optimise their performance and reduce the risk of injuries.
Key Points:
- Women should ensure adequate calcium and vitamin D intake to support bone health.
- Weight-bearing exercises like running, dancing, and resistance training are beneficial for maintaining bone density.
- Pair a heavy training session with the first stage of the menstrual cycle (Follicular Phase).
- Post-menopausal women may need to consider hormone replacement therapy (HRT) to mitigate the effects of decreased estrogen on bone health, after consulting with a healthcare provider.
- Neuromuscular training programs that focus on improving balance, strength, and agility can reduce the risk of ACL injuries.
References:
- Khosla, S., Oursler, M.J. and Monroe, D.G. (2012) ‘Estrogen and the Skeleton’, Trends in Endocrinology & Metabolism, 23(11), pp. 576–581. doi:10.1016/j.tem.2012.03.008.
- Chidi-Ogbolu, N. and Baar, K. (2019) ‘Effect of estrogen on musculoskeletal performance and injury risk’, Frontiers in Physiology, 9. doi:10.3389/fphys.2018.01834.
- Sutton, K.M. and Bullock, J.M. (2012) ‘Anterior cruciate ligament rupture: Differences between males and females’, Journal of the American Academy of Orthopaedic Surgeons, 21(1), pp. 41–50. doi:10.5435/jaaos-21-01-41.
