By Ed Shepherd CHC, CPT
Resistance/strength training is an exercise, or set of exercises, that helps the different muscles in your body to become stronger and more powerful.
Resistance training may include free weights and machines, body weight exercises like push ups or pull-ups, planks squats and lunges, and kickboxing. When a person has stronger muscles, they will have additional strength and stamina for daily activities. If a person’s body muscles are strong it also means that the body is more likely to recover quickly from injuries, and it is sure to burn calories more efficiently and effectively.
Physical Capacity is the ability to perform work or exercise. Muscles utilize energy to produce forces that enable people to move their body parts and any external resistance, thereby functioning as the engines of the body. Resistance training results in stronger muscles that increase the physical capacity for force production. Progressive resistance exercise enables a person to perform a single lift with a heaver weightload (muscular strength), and to preform more repetitions with a sub-maximal weightload (muscular endurance).
Physical Capacity decreases dramatically with age in non-strength adults due to an average 5-pound per decade loss of muscle tissue (atrophy). Consequently, if you want to maintain your physical capacity and performance abilities you must make resistance exercise a regular component of an active lifestyle.
Physical Appearance and Body Composition
The human body is composed of two primary components – fat weight and fat-free weight, or lean weight. Lean tissue consists of muscle, bone, skin, organs, and connective tissue, with muscle contributing about half of the lean weight (a little more than half in men and a little less than half in women) and lean mass is subject to progressive decreases associated with aging and with a lack of raining.
A women who does not strength train loses about 0.5 pounds of muscle each year. For example, if Mary is 30 years old, weighs 120 pounds and has 20% body fat, she has 24 pounds of fat weight and 96 pounds of lean weight, of which 45 pounds is muscle.At age 50, if Mary weighs the same (120 pounds) her body composition would change by 20 pounds.
- Loss of 0.5 pounds a year – 10 pounds less muscle in 20 years
- Gain of 10 pounds of fat in 20 years
- Fat mass: 34 lb
- Lean mass: 86n lb
- Percent body fat: (34 lb/120 lb) x 100 = 28.3%
Of course, this increase in percent body fat has a negative impact on her appearance, fitness, and health. Fortunately, a basic program of resistance exercise can reverse this situation. Numerous studies have shown that several weeks of strength training result in about 3 pounds more muscle and about 4 pounds less fat in adults and in older adults, and this rate of body-composition improvement appears to continue for several months.
Muscle tissue is constantly active for purposes of maintenance and redoing of muscle proteins. Even during sleep, resting skeletal muscles are responsible for more than 25% of the calorie use. The 5-pound per decade muscle loss experienced by non-strength trained adults leads to a 3% to 8% reduction in resting metabolic rate associated with the gradual increase body fat that typically accompanies the aging process. When less energy is required for daily metabolic function, calories that were previously used by muscle tissue are stored as fat.In contrast, strength training raises resting metabolic rate and results in more calories burned on a daily basis. One study reported an average of 9% increase in resting metabolic rate for three days after an intense workout in untrained individuals and an average of 8% increase in resting metabolic rate for three days after an intense workout in trained individuals. Apparently, the microtrauma-repair and muscle-remolding processes require increase energy for at least 72 hours following strength-training session (after burn effect). If you perform resistance exercise at least every third day, the elevated metabolism would seem to be a continuous physiological response to regular strength training.Given a typical resting metabolic rate of about 1,500 calories a day, an 8% elevation represents 120 additional calories burned at rest on a daily basis. Other things being equal, this would total 3,600 more calories used every 30 days, for a 1-pound fat loss per month and a 12-pound fat loss per year. It is clear that resistance exercise can increase muscle mass, decrease fat mass, and increase resting metabolic rate, effectively countering primary degenerative process of sedentary aging. Additionally, the calories used during the strength -training session and in the post-exercise muscle-remodeling period contribute to fat loss and provide associated health benefits.
Injury Risk and Disease Prevention
Muscles serve as shock absorbers and balancing agents. Strong muscles help to dissipate the repetitive landing forces experienced in weight-bearing activities such as running and step exercises. Balanced muscle development reduces the risk of overuse injuries that can result when one muscle is relatively strong and the opposing muscle group is relatively week. A program of resistance training that addresses all of the major muscle groups may be the most effective means of preventing various musculoskeletal injuries and reducing the risk of many degenerative diseases.One of the most direct benefits of regular exercise and strength training is increased bone density, which may reduce the risk of osteoporosis. Other benefits of resistance trying include:
- Improved body composition (more muscle less fat) which reduces the risk of type 2 diabetes and cardiovascular disease. With respect to diabetes, resistant exercise has been shown to improve insulin response and glucose utilization. With respect to cardiovascular disease, strength training has been demonstrated to lower resting blood pressure, improve lipid profiles, enhance vascular condition, and decrease the risk of developing the metabolic syndrome.
- Stronger muscles, which is particularly important for low back health. Stronger erector spine muscles enhance (muscles vertically up the length of the back), control, function, and shock absorption. After performing 10 weeks of resistance exercise for the lumber spine muscles many individuals with low back function and pain have had improvement.
- Reduced pain of osteoarthritis and rheumatoid arthritis.
- Decrease in depression in older men and women.
- Improved functional ability.
- Increased mitochondrial content and oxidative capacity of muscle tissue. In one study , older subjects who had six months of circuit training experienced positive adaptations in 179 genes associated with age and exercise, giving their muscles mitochondrial characteristics similar to those of young adults.
Finally, research has demonstrated numerous health and fitness benefits resulting from regular resisting exercise. Taken together, their benefits enhance the quality of life and lower the risk of premature all-cause mortality.