Sit-ups and crunches might be good for your abs, but they're potentially damaging for your back. These exercises are not as effective as many alternatives and, worse, they can contribute to spinal issues such as herniated discs. A sit-up or crunch compresses the spine and encourages movements that are not well-mimicked in any physical activity, making these exercises a poor choice for abdominal strengthening. Choose an exercise such as the plank for all the strength-building without any of the back pain.
Sit-ups and crunches involve a repeated flexing of the spine. Even on a soft surface, this motion can cause compression of your spinal discs, causing them to bulge and press on nerves. This condition can worsen from back pain to a serious medical condition. This rapid compression and decompression degenerates the fibrous outer walls of your discs, causing them to herniate over time. A herniated disc can become painful enough that it requires surgery to correct.
Investigating Back Pain
Several studies and books have investigated the various causes of herniated discs, and the topic lacks a consensus. In ongoing research of pairs of identical twins, published in 2009 in The Spine Journal, back pain was not necessarily linked to activities — genetics played a big role. Depending on your physiology, a modified routine of sit-ups and crunches may be the best alternative. Researcher Bret Contreras from the Auckland University of Technology in New Zealand recommends 60 repetitions per session, with only 15 crunches or sit-ups to start. Contreras also advises against practicing sit-ups first thing in the morning; your spine lengthens overnight, making it more susceptible to damage from compression.
As the sit-up and crunch are phased out of many workout plans, fitness experts are turning to other exercises for ab strengthening. The plank pose, which resembles the upward portion of a push-up, is a powerful stationary exercise that better engages the muscles of your core without any of the back pain of a sit-up or crunch. Other variations of the plank and various yoga poses approach ab strengthening in a similar way. Engage in workouts that mimic the real-world motions that engage core muscles; lifting, dragging, pulling and pushing heavy objects such as sandbags or weights helps prepare your abdominals for tasks you might actually encounter in real life.