Knee-Pain Lowdown

Squats have always been a controversial exercise. While often called the king of exercises because of its superior overall growth-promoting effects, the squat is also the source of an ongoing debate among strength trainers and scientists. Few would argue that squatting with poor exercise form is risky. That includes bouncing out of the bottom position, dropping down too fast and leaning so far forward that the lower back is unduly stressed.

Others contend that squats build up the glutes and hips too much, producing a big-ass appearance. A few even suggest that they cause the midsection to bloat, producing the potbelly seen on many of today’s competitors. Of course, that doesn’t explain the rarity of that deformity in years past, when doing heavy squats was standard’or the fact that many current professional bodybuilders never do heavy squats yet have bloated midsections.

In the 1960s one exercise scientist declared that squats’particularly full squats’were inherently dangerous and likely to produce knee and joint trauma. While those warnings didn’t pan out, since few, if any, bodybuilders wound up with bum knees from years of squatting, a new study involving Chinese people makes you wonder about just how safe squatting is.

More than 1,800 people from Beijing over age 60 underwent knee scans to detect osteoarthritis and estimated the average amount of time each day they’d spent squatting at age 25.1 Squatting is common in China, during both rest and work.

The men who reported squatting more than three hours a day were twice as likely to have knee osteoarthritis than men who squatted less than 30 minutes a day. The risk increased by 70 percent in men who squatted two to three hours daily, as they suffered from tibiofemoral arthritis, or erosion of the joint between the thigh and shin bones. Squatting also increased the risk of arthritis in women, especially in those who squatted more than three hours a day.

The Chinese women showed a 10 percent more common incidence of arthritis than American women of the same age. Yet Chinese men, despite their extensive squatting, were less likely to have arthritis than their American counterparts. That paradoxical finding probably relates to the fact that Chinese men get more physical activity than their American counterparts and that they tend to carry less weight. The onset of knee osteoarthritis has a direct relationship to bodyweight, with obesity being a major risk factor.

So what’s the take-home message for bodybuilders and other strength athletes? Few bodybuilders ever squat for three hours a day, but they also often pile prodigious amounts of weight across their backs while doing squats. Ronnie Coleman, for example, often squats with 800 pounds during the off-season. One can only surmise how many hours of weight-free squatting that represents.

The Chinese study didn’t involve weighted squats but did feature a deep-squatting position held for extended times. That tells me that doing full, ass-to-the-ground squats is likely to increase the incidence of tibiofemoral arthritis. I don’t believe the risk occurs with so-called half, or parallel, squats, in which the exercise ends with the thighs parallel to the ground. Those are more likely to help protect against arthritis, since inactivity and lack of exercise are themselves risk factors for the disease. IM

1 Zhang, Y., et al. (2004). Association of squatting with increased prevalence of radiographic tibiofemoral knee osteoarthritis: the Beijing osteoarthritis study. Arth Rhumat. 50:1187-92.