The initial sudden, sharp pains can be similar, but the way to treat a muscle cramp or spasm versus a muscle or tendon strain or tear can be totally different. Also different is what the pain signifies and how long it will take to recover.
A muscle cramp or spasm can occur when you ask your body to do more than it is trained for. Sometimes it is the body’s protective response; for instance, in the lower back, where a spasm and concurrent sharp pain may help prevent more serious damage to the spine.
A muscle strain or tear can be of various degrees, starting with “micro-tears,” which cause muscle soreness, but can be part of strenuous training, with the body becoming stronger after recovering. In between is a partial muscle tear, where there is a tear in the muscle. Most dramatic is the complete muscle or tendon tear or rupture, for instance with the Achilles tendon, where the structure is totally separated and surgery is usually the only answer.
When you have a muscle or tendon tear, the damage has already occurred, and the only thing you can do is rest while the tissue heals, by depositing scar tissue. If you use the damaged area before the healing process is complete, you run the risk of re-tearing the same area, forming more scar tissue, and delaying the time when you can exercise normally again.
I discovered the dangers of running through an injury like this when I was in my late 20s, and attempting to qualify for the Olympic Trials Marathon. I was running 100 miles per week, training with the William and Mary cross country team, and was in the best shape of my life, when a sharp pain occurred at the junction of the Achilles and the calf. I limped home, but had recovered enough in a week to resume normal training two weeks later I started the Marine Corps Marathon in my quest for a qualifying time. While the injury had healed enough for regular training, it had not healed enough to put on racing flats and run at race pace for a full marathon. Predictably, the pain reoccurred midway through the marathon and I dropped out at 18 miles, damaged goods again.
For the next two months, I repeated the pattern of partial healing and further tissue damage, naively thinking that eventually I’d just take two to three weeks off and all would be well. It wasn’t. What I didn’t realize then, but do now, is the insidious nature of scar tissue. Scar tissue is deposited randomly at the site of the injury as the body’s first response to tissue tearing. It can eventually become more flexible, elongate and transform into regular muscle tissue, but if you abuse the process, the lump of scar tissue becomes increasingly large and inflexible and the recovery takes much longer. That happened to me, and I was forced to become a fitness runner for two to three years.
When you have a muscle tear you must come back slowly, gently nursing the affected area back to its original strength and flexibility. In contrast, when you have a muscle cramp or spasm, there is not yet any lasting damage to the muscle tissue. When the muscle cramps up, it forms a knot, effectively shortening the length of the muscle, and putting potential stress on the tendons attaching the muscle at each end, or on the muscle itself. If you continue using that muscle, then actual damage can occur to the muscle in the form of a tear, or of a strain to the adjacent tendons.
Depending on the severity of the cramp/spasm, that recovery process can take as little as one day or as long as a week or more. To hasten recovery, you can massage the area, apply heat after the first 24 hours, try physical therapy or gently use the cramped area, perhaps by just walking. The most important treatment is time—allowing the cramped area to ease up naturally before resuming intense exercise.
As with all injuries, you’ll want to analyze why it happened in the first place and avoid doing the same thing again. That could mean replacing old, worn-out shoes, working on strengthening exercises, warming up more gently, or just increasing the training intensity at a slower degree.