Summer is here and we all are getting more active with different outdoor activities from gardening to running and water activities. That’s great because physical activity and exercise have both temporary and continual effects to cardiovascular function, tissue perfusion, metabolism, hormonal balance, and musculoskeletal tissues.
The maintenance of normal bone, tendon, ligament, cartilage, and muscle requires a steady level of repetitive load. Activity below this level causes negative changes. The intensity and frequency of activity above minimum level results in an adaptation to load. This specific adaptation to imposed demand is a foundation to all exercise. Too strenuous exercise beyond the adaptation ability of the tissue may lead to tissue damage and injury. Pain during physical activity or while exercising is a sing of tissue irritation and therefore should be avoided in order to prevent injuries and to put off further irritation of an existing injury or musculoskeletal condition.
Persistent cyclic loading of the bone is known to cause bone formation to exceed bone removal that can result in increase in bone density, volume and strength. Strenuous exercise causing muscle fatigue leads to a loss of muscles’ shock absorbing capacity and abnormal loading of the bone. This altered stress distribution may lead to stress fractures.
Increased loading and motion of joint articular cartilage, like moderate fast walking and running (2.5-3.0 miles/day, 3-5 days / week), may increase cartilage thickness and promote the overall health of the cartilage. Strenuous long distance running (25 miles / day for 15 weeks) is enough to damage joint cartilage causing derangementation, fibrillation, injury, and osteoarthritis.
Normally muscle tissue, joint capsules, and ligaments are absorbing 80%-90% of the force and articular cartilage is absorbing only 10%-20% of the force in joints. If extra-articular tissues ability to absorb the load is decreased, more stress is put on the cartilage. It is extremely important to maintain healthy musculature to avoid an overload of bone and articular cartilage. Anybody with decreased muscle strength or with existing cartilage problem needs to build up the walking / running time / distance gradually while also improving their lower extremity muscle strength.
Persistent increased load changes the structure, functional capacity, and volume of skeletal muscle. Low-resistance, high-repetition training primarily increases muscle endurance and high-resistance, low-repetition training primarily increases muscle strength. Increased muscle endurance is needed for daily activities. It also enables better posture and position during activities. The high-resistance exercise may be used to increase functional strength and to improve muscles’ shock absorbing capacity. Reduction in frequency or intensity of activity causes a decrease in muscle mass and strength rapidly.
Repetitive loading can also increase the strength, size, and organization of tendons, ligaments, and their insertions to bone. Low resistance, high repetition training facilitates bone, cartilage, tendon and ligament vascularisation and may increase it’s strength by 30%-40%. Endurance training also advances muscle performance and coordination enhancing the function.
Although all musculoskeletal tissues are responding to repetitive load, they all are sensitive to specific patterns of loading. Keeping that in mind and knowing that too strenuous loading may damage the tissues, we need to use various different ways of exercising. We need to exercise on mild to moderate levels on a regular basis using primarily endurance type of training but not forgetting to include weekly strength training in to our exercise programs. Summertime biking, walking, running, swimming, and strength training can be the bases for better quality of life.
If you have any questions regarding your musculoskeletal condition and exercise, please e-mail OrthoSport at orthosport@comcast.net or give us a call at 734-961-9626.
Enjoy your Holiday weekend and have an active summer,
Veli