The most obvious positive effects of strength training include more efficiency in muscle function and possibly even larger muscles, but one of the more important effects that is not always noticeable is a larger store of glycogen, which is the body's preferred fuel source during physical activity. Strength training can also help boost one's metabolism, which can aid in losing weight and boosting energy. This metabolism boost can also improve mood and battle some difficult conditions such as depression. Obese people can benefit most from the effects of strength training, as this training can help reduce the likelihood of conditions such as hypertension.
When the body needs fuel during physical activity, it has two general choices: glycogen, which is easily burned quickly and stored for long-term use, or fat, which is slow to burn and therefore not efficient for physical activity. The effects of strength training include the ability to create and store more glycogen and burn fat more quickly, thereby making the body work more efficiently. When glycogen burns, it produces a by-product called lactic acid, which can cause soreness or stiffness after or during exercise. Another one of the effects of strength training is improvement in the lactic acid threshold, or the amount of lactic acid that can build up in the muscles while still allowing the exerciser's muscles to function thoroughly.
Improved blood flow and oxygen delivery to muscles are more effects of strength training. The more blood that flows to the muscles, the more oxygen will reach them, and consequently, the more efficiently the muscles will function. This improved blood and oxygen delivery will also speed up recovery should injuries occur. Many argue that this improved blood flow also improves one's mood, since oxygen delivery to the brain will be increased, and certain chemicals that affect mood are produced during exercise.
Strength training can also improve one's balance and coordination. The stimulation of the muscles improves the response of the central nervous system, which can in turn improve coordination. Balance will be improved for the same reason, but it will also be improved because as the muscles of the body begin to develop, they will more adequately support the spine and hips, which greatly affects one's balance. Stronger muscles are also less likely to tighten, which means they will not pull on bones in the spine, hips, and legs. If the spine is misaligned, balance is likely to be adversely affected.