Stretching is not necessarily needed before strengthening; however, stretching can be performed afterward with at least 30 seconds of stretch per muscle group.
WRONG would be bad form, too heavy, not enough rest, too many sets
Rep ranges are 10-15, 3-7 sets, about 10-20 per body part per week, rest 3-7 days depending upon...well...many factors.
“Another way to minimize risk is to follow a machine-based program, at least initially, where the range of motion is predetermined,” “But it’s free weights that will ultimately produce the best technique and posture and, consequently, muscle gains.”
On paper, the benefits of weight training for teens and adults are the same: increases in muscle mass, tendon and ligament strength, muscle endurance, flexibility and coordination. But youths, particularly those who have gone through puberty, have the benefit of a hormonal surge that increases the response to the training stimulus.
“After puberty, testosterone production is maximized, and both androgenic and anabolic effects take place,”
Testosterone levels, which increase as a result of weight training regardless of age and gender, are central to muscle growth. It’s understandable, then, that a natural spike in this hormone would lead to even greater gains for a teenager engaged in a program of regular, progressive weight training.
But even before this Wonder Years—induced hormonal peak, lifting elicits plenty of benefits. EVEN Before puberty, weight training can improve neural activity and muscular recruitment patterns,”
But how young is too young? 8 is ok WITH a trainer that knows what they are doing. The key is that the training must be taught correctly and supervised constantly. The ideal age to start a general resistance program is 11, when you can reinforce technique and movement skills. True resistance training for the purposes of hypertrophy [muscle growth] is best saved for 14.”
Weighted exercises such as the squat, bench press, overhead press and bent-over row should be comple-mented by bodyweight exercises such as the push-up, pull-up and step-up. “They also recruit the most muscle, which is key for maximizing hypertrophy.”