Fitness, increase strength, without increasing weight methods are as follows

First, leg strength training: 1, one leg jump; 2, leg jump; 3. On the singles and doubles line, jump on the line with one leg left and one leg right respectively; 4. Jump over obstacles with one leg; 5. Clean and jerk with barbell, squat with weight, squat with weight, and twist with weight.

Second, develop arm strength training: 1, throwing the ball with both hands bent, 2, throwing the ball with one hand (tennis), 3, holding Yaling's recommendation, straight arm lifting, forward bending lifting, arm bending lifting, etc.

Third, develop waist and abdomen strength training: 1, sit-ups, 2, sit-ups and turns, 3, sit up, 4, bend over and throw forward with both hands holding the ball.