Circuit training is a mix of strength training and endurance training. In a circuit-training workout you do a group, or circuit, of exercises with little or no rest in-between. Usually, one circuit consists of 6 to 10 exercises. Each exercise is performed for a set number of repetitions or period of time before moving to the next exercise. For example, you might do squats for 15 seconds, rest 15 seconds, and then do bench presses for another 15 seconds followed by other exercises. Depending on your fitness level, you might do one circuit or several circuits during each workout.
Here are two examples of circuit training workouts. The first workout can be done at home and the other can be done at the gym or with the Keiser Machine:
Circuit-training workout #1 : Lunges are counterbalanced with a 30-second hip flexor stretch with a chopping motion of the arms towards the hip flexor being stretched. Squats are counterbalanced with Swiss-ball or TRX roll outs for core muscle integration.
Circuit-training workout #2
It can also be misleading to judge the exercise's effectiveness on particular muscle group based upon localized muscular fatigue. Often times beginners feel muscular fatigue in unusual places until they become accustomed to that exercise. The weak link analogy can be attributed to this phenomenon.
Training mode should be very similar the sport activity (surfers should surf, runners should sprint, cyclers should cycle hills, etc.)
Cross training should complement the specific muscle training done during sports participation with core muscle and stability strengthening.
Exercises that utilize the largest muscles (Glutes and Quads) may have greatest potential in increasing post exercise metabolism. Resting basal metabolic expenditure accounts for fat burning throughout the day even while at rest.
Exercise programs increase muscle strength and flexibility in the elderly. This should be a no-brainer! Nevertheless, here is the research:
(JAMA- FICSIT Trials 1995; 273:1341; Journal of the American Geriatric Society 1996; 44:513)
Resistance training improves weakness which is more of a limiting factor than endurance (J Am Ger Soc 1994; 42:937) in preventing falls
Strength training of the whole body appears to be more beneficial than isolating an affected joint in osteoarthritis patients.
Warm water exercises (~86 degrees Farenheit) provide analgesia for painful muscles and joints (Arthritis Rheum 1999;42(7):1361-1369)
Effects of exercise and hormone replacement therapy are additive in osteoporotic women (Osteoporosis Int 1999;9(1)1-12)
Tai Chi cardiorespiratory function better among older Tai Chi practitioners (J Am Ger Soc 1995;43:1222)
Tai Chi decreases falls (J Am Ger Soc 1996; 44:489,498)