Sub Max Isometric Exercises

Sub maximal, or sub max, isometric exercises is a type of training used to build strength at targeted parts of the body and to rehabilitate injuries. Maximal isometric exercise is similar in many ways to sub max isometrics, but it involves pushing or pulling immovable objects. Sub max isometrics can help you build strength and muscle size by forcing your muscles to recruit as many muscle fibers as possible to complete the action, which in turn builds strength and muscle size. A few examples of sub max isometric exercises include planks, wall sits and lateral dumbbell holds.

  1. The Good

    • Significant strength gains of up to 40 percent are possible over a 10-week period using isometric exercise, according to T Nation. Holding the pose, dumbbell, barbell, or source of resistance for 10 or more seconds leads to the greatest gains in muscle size. Aside from being efficient at building muscle, sub max isometric exercises are ideal for rehabbing an injury. Since you don’t use the full range of motion of your joints, sub max isometrics are often less painful to perform after joint and muscle injuries; you can build strength and speed up recovery without re-aggravating the injury.

    The Bad

    • Even though you can build lots of strength, power and muscle size with sub max isometrics, the strength gains only occur at the joint angle being worked. This greatly limits your dynamic strength gain throughout the entire range of motion of your joints. This makes sub max isometric training a poor choice for athletes trying to build dynamic strength, such as sprinters and basketball players.

    How to Do It

    • There are several ways to do isometric exercises. For building muscle size and strength, choose a resistance level of about 60 to 80 percent of your one rep max, or 1RM. Hold the resistance in a static position for at least 10 seconds and do eight to10 reps per exercise. For rehabilitation purposes, a lighter resistance level is preferred to reduce the chance of further injury – 50 percent or less your 1RM. The type and severity of the injury plays a major role in how much resistance to use and the duration of each rep, so consult a physical therapist if rehabbing an injury with sub max isometric exercises is your intent.

    Who it’s For

    • Rehab patients aside, sub max isometrics is beneficial to some athletes and people looking to add variety to their workouts. Sports that require static strength may benefit from isometrics, including judo, skiing, shooting, gymnastics, dirt bike racing and wrestling. If you’ve hit a plateau in the weight room and strength gains have come to a screeching halt, isometrics may help get you over the hump. It never hurts to add some variety to your workout routine to help challenge your muscles in a different way. Add a few sub max isometric exercises to your usual workout routine and see if it helps improve your gains. You can do an isometric contraction using any of the exercises you currently use, including bicep curls, any abdominal exercise, bench press, squats and any dumbbell exercise.

    Sub Max Exercises to Try

    • An effective sub max isometric exercise for your abs is the plank position. Simply lay your forearms flat on the floor beneath your chest and hold your body up with your forearms and toes -- sort of like a pushup position. Train your legs using wall squats. Place your back flat against a wall and lower your body into a seated position where your knees are bent at about 90 degrees -- hold the position as long as you can. Target your chest, arms and abs by doing isometric pushups. For this one, hold a basic pushup position lowered about halfway down to the floor. Hold each position for as long as you can, and repeat two or three times.