Muscle tension is a normal performance, because you trigger your muscles during exercise, which causes the biceps brachii to be in a state of tension. We know that biceps brachii plays a stretching role in physiological exercise, so when biceps brachii is in a state of tension, the arm cannot be straightened.

Moreover, in daily life, the utilization rate of the right hand is generally several times higher than that of the left hand (the opposite is true for the left hand), so the arm muscles have been well exercised in daily life, but the muscles of the left arm have just been stimulated, so there will be some discomfort after training.

Warm-up exercises before fitness include: positive leg, side leg press, leg-lifting running, including chest vibrating arm, neck ring and shoulder ring, and doing a little.

In fact, the best stretching method is to wait until the next day to train. It is normal for muscles to be sore and nervous at the beginning of training. Usually, we call this phenomenon "fatigue period". People with good physique have a fatigue period of almost 3 days, and it will be fine after the fatigue period.

If you don't want to keep your muscles tight after training, you can stimulate your muscles out of thin air and rub them for a short time.

However, when your muscles are completely tense, you will be the most suitable, because as long as you train enough, all your muscles will be triggered, but we can't make every muscle nervous out of thin air.