Biceps curls for everyone
You can perform biceps curls using dumbbells, elastic bands, weighted bars or machines designed specifically to train this muscle. As long as you are providing appropriate resistance, the muscles will respond by strengthening. You also can do this exercise seated or standing. If standing, the postural muscles, particularly the abdominals and low back, are worked to a greater degree than if seated.
Traditional technique: Hold weights in each hand with a full grip (thumbs wrapped securely around the handles). Lower your arms so that they are straight and next to your sides, palms facing forward. Gently squeeze the shoulder blades together and down to keep the shoulders from hunching or rounding forward. This position is the lengthening phase of the exercise.
Next, slowly bend your elbows and bring the weights toward your shoulders. Try to keep your elbows from traveling forward or away from your sides, and avoid letting the wrists bend when lifting. This is the muscle contracting/strengthening phase of the exercise.
Here are some variations.
Hammer curls: Instead of palms facing front, turn your palms inward, so that they face your sides.
Preacher curls: With this variation, use a preacher curl machine or drape the arms over a surface so that the elbows are in front of the body as the weight is lifted. Avoid overextending the arms, which can put strain on the elbow joint.
Concentration curls: This variation is performed seated, holding a dumbbell in one hand. The upper body is leaning forward slightly, with the elbow placed on the inside of the same side knee, and arm straight. Lift the dumbbell upward toward your shoulder while keeping your upper arm still. Pause briefly and then slowly lower.