If holding the classic plank for at least 3 minutes is not a problem for you (make sure, you’re doing it with correct technique) – you can differ your training program and work better on oblique abdominals, by doing the side plank. In this exercise part of the load is taken off the spine, so even those, who has been recovering from injuries and feel discomfort in lower back when doing the classic plank, can do it.
What muscles work: oblique abdominals, buttock muscles, erector spine muscles.
Performing the exercise: stand in the emphasis lying on the side, leaning on one hand’s pre-shoulder and opposite leg’s foot (for right hand – on left and the other way round). At the starting position shoulder joint should be right above the elbow, pre-shoulder of the base hand – perpendicular to body. Using your muscles hold the whole body straight (photo 1). Having fixed the position, hold it for required time, after that go back to the starting position and repeat the exercise switching hand and leg.
Notice: do not lean on foot, that is at the bottom – contact area will be less, which leads to sliding, just put it on base leg’s foot. Watch the body position, don’t let lower back bend or lean front or back. Avoid bending your knees, keep them straight using buttock and hip muscles. Spread shoulders, stretch hands by the body, put on belt, raise up or behind your head (two last variations make the exercise a little bit harder, so raise the load gradually). Don’t bend your neck, you should look forward (on base hand’s pre-shoulder). If you are exercising on hard floor – put something soft under your base hand (for example, several times bent towel). Gradually raise time of holding the side plank to 3 minutes.
If it’s difficult for you to perform the side plank in classic look, try to lower the load by changing body tilt angle – at the starting position lean not on pre-shoulder, but on straighten hand (photo 2). While doing this, the main rules stay the same: all the three joints (wrist, elbow and shoulder) are situated one above another, base hand should be perpendicular to the floor, whole body is held maximum straight, without bends, hangouts or front-back leans. You can regulate the load by inactive hand and leg position: firs, situate them parallel to the floor, but gradually raise them higher (you can put the hand behind your head).
The other variation of lightened side plank is the emphasis lying on one pre-shoulder and one calf (photo 3). Lower load is reached by reduced participating body length. For the starting position bend the base leg in knee and put it so that knee joint was an the base hand elbow joint’s level. Using your muscles straighten the body and hold for the required time. Hold to the main side plank rules, written above. You can hold an inactive leg bent in knee or straighten (that is a little harder, but gives the additional load on inactive hip muscles).
If you have mastered variations, suggested here and can hold the classic side plank at least 3 minutes, you can try complicader variation, providing more horizontal body position. To perform this exercise you will need a 20-30 cm pillar. Stand in the emphasis lying, as for side plank, but put the opposite leg’s foot on the pillar. Straighten body using muscles and hold for required time (photo 4). The core should be straight, do not let your lower back bend inside or outside, as well as tilting forward or backward. Watch your breath, don’t hold it, try to breathe rhythmically. Since the elbow joint gets increased pressure – put something soft under it (for example, bent towel).
When you master this kind of plank (can hold the position at least 3 minutes), try to complicate the performance a little more, by putting legs on an unstable pillar – for example, ball. You can also change the load with inactive leg’s position, rising it up or even aside (which requires additional force to hold the balance). It will be difficult, but this is pro level. I’m sure you can do it!
Good books to read:
Bret Contreras. Bodyweight Strength Training Anatomy – Human Kinetics, 2013 – 224 p.
Kavadlo Al. Pushing the Limits: Total Body Strenght with No Equipment – Dragon Door Publications, 2013 – 224 p.
BJ Gaddour. Your Body Is Your Barbell: No Gym. Just Gravity. Build a Leaner, Stronger, More Muscular You in 28 Days – Rodale, 2014 – 288 p.