Debunking Exercise Myths, Part I
by Eric Cressey
We live in a society that doesn't want gray areas. People want right or wrong, up or down, and left or right. This mindset carries over to the gym, too; lifters want to be able to say that Exercise A is evil, and Exercise B is safe.
Unfortunately, it's not that simple, so with that in mind, I'm devoting this article to killing off some myths, establishing some more well-defined gray areas, and making recommendations on who can do what.
I'm going to come right out and say it: in the absence of musculoskeletal pathology, no movement is fundamentally bad. Sure, there are exercises like kickbacks and leg extensions that don't give you as much bang for your buck as their multi-joint counterparts (e.g. dips and squats), but that's not to say that these pansy exercises are "bad" for you. Likewise, it's rare that I write any sort of machine lift into my programming, but there are rehabilitation patients that benefit greatly from certain machine training.
In my opinion, there are only five scenarios in which exercise is ever truly bad for you from a health standpoint:
1. When that exercise is performed in excessive volume.
2. When that exercise is performed with poor technique.
3. When that exercise is performed in a manner that puts it out of balance with the rest of the programming that is in place.
4. When that exercise irritates an existing injury or condition.
5. When that exercise is performed with excessive loading (relative to the lifter's capabilities).
Now, it's not feasible for me to outline every specific instance where every exercise is safe or unsafe, but I can address some common adages we frequently hear in our gyms.
Adage #1: Your knees shouldn't pass your toes when you squat.
First off, you need to consider whether you're a powerlifter or a bodybuilder. In other words, are you planning on hammering your posterior chain by using predominantly the hamstrings, glutes and lumbar erectors to complete the movement? Or, are you looking to overload the quads?
It goes without saying that the movements are significantly different, so it's important to first differentiate between the two. In the powerlifting squat, you'll be sitting back, arching hard, and attempting to keep the shins perpendicular to the floor; in other words, there will be more trunk flexion, thus facilitating recruitment of the hip extensors and enabling you to get to parallel easier.
While the knee extensors are going to be involved to some extent (as there is knee flexion occurring on the eccentric), it's the muscles acting at the hip that account for the majority of the force that brings you out of the hole. It is, however, virtually impossible to squat rock bottom with a powerlifting style squat; your chest would be on top of your thighs far before your hamstrings hit your calves (unless you have freaky big hamstrings and calves).
In the Olympic version of the squat, initiating the movement is still about sitting back, but not nearly to the same degree as the former example. Essentially, we're looking for a happy medium between sitting back and sitting down. The knees are going to come in front of the toes simply because this is the only way to get deep when the trunk is more upright; if the knees stay directly above the toes on an Olympic squat, your base of support is too narrow, your center of gravity is shifted backward, and you fall backward (and still don't get your depth). You see this all the time in beginners. It's almost as pathetic as when they talk on their cell phones in the gym.
So, the question arises of whether or not the knees coming in front of the toes during the Olympic squat is dangerous. Fry, Smith, and Schilling (2003) examined joint kinetics during back squats under two conditions.(1) In the first condition, a board placed in front of the participants' shins restricted the forward displacement of the knees. In the second condition, movement wasn't restricted at all; they squatted normally, and the knees passed the toes (gasp!).
The researchers found that restricting the forward excursion of the knees during the squat increased anterior lean of the trunk and promoted an increased "internal angle at the knees and ankles." The results were a 22% decrease in knee torque and a 1070% increase in hip torque!
Sure, they "saved" the knees by limiting stress on them, but those forces were transferred more than tenfold to the hips and lower back! The researchers concluded that "appropriate joint loading during this exercise may require the knees to move slightly past the toes". "May?" Ugh. I mean honestly; look at these photos that the authors included. Isn't the lumbo-pelvic position in "B" just lovely?
Source: Fry and Smith, 2003, J Strength Cond Res.
In consideration of this study and photo "B," some might wonder whether powerlifting squats are safe on the hips and lower back. My answer is a resounding "YES" for several reasons. First, powerlifters attempt to minimize, not eliminate, the knees coming in front of the toes. There is always going to be at least subtle anterior excursion of the knees relative to the feet.
Second, powerlifters know to sit back and not down when they squat; the participants in this study were still attempting to do the latter when they performed the restricted squats. If you try to Olympic squat with the shins perpendicular to the floor; your lower back is going to round... period. Engaging in this debate would amount to comparing apples and oranges.
Third, powerlifters are proficient at establishing and maintaining a tight arch of the lumbar spine; this position is crucial to keeping the chest up and, in turn, the center of gravity within the base of support (or else the movement becomes a good morning). This position also places the hamstrings at a mechanical advantage.
Fourth, powerlifters assume a squatting stance that is at least a little wider than that of Olympic lifters; this repositioning "opens up" the hips and enables one to get deeper without considerable forward excursion of the knees.
Fifth, photo "B" is not a powerlifting squat; it's just a mess of torso and limbs with a bar on top.
Adage #2: You should not squat below parallel.
I'm on a roll with the squatting issue, so I might as well stick with it. Let's get something straight right off the bat: the "parallel" designation is something that was not borne out of any biomechanical rationale whatsoever. Rather, it is a product of needing a way to determine if the squat is completed in lifting competition. Where people lost sight of this fact is beyond my comprehension, so I'll simply ask this: would you use partial range of motion on other exercises in a healthy individual without any exercise contraindications? I didn't think so. Although this reasoning ought to be enough for most of you, how about a little literature to back this up?
Salem and Powers (2001) looked at patellofemoral joint kinetics in female collegiate athletes at three different depths: 70 degrees (above parallel), 90 degrees (at parallel), and 110 degrees (below parallel) of knee flexion. The researchers found that "Peak knee extensor moment, patellofemoral joint reaction force and patellofemoral joint stress did not vary significantly between the three squatting trials (2);" there was no support for the idea that squatting below parallel increases stress on the patellofemoral joint.
It's important to also note that squatting depth should be determined by the athlete's flexibility and goals, as well as the nature of his sport. If one doesn't have the flexibility to get below parallel safely, then the rock-bottom squat shouldn't be part of his arsenal; this athlete's attention would be better devoted elsewhere and possibly supplemented with squats at or above parallel.
It stands to reason that different athletes will have different goals in light of the demands of their sports, too. For instance, Olympic lifters and rock climbers would require positions of deep closed-chain knee flexion more often that offensive linemen and marathoners. Then again, the nature of some sports requires that deep squatting be used to offset the imbalances that result from always working the knee extensors in the 1/4 and 1/2 squat positions; this is one reason that cyclists, hockey players, and athletes who do significant amounts of running (e.g. soccer players, marathoners) ought to prioritize deep squatting and single-leg movements early in the off-season.
Finally, it's important to remember that while a full range-of-motion squat will offer noticeable carryover to top-end strength, 1/4 squats will not yield strength increases in the lower positions. Effectively, you get more bang for your training buck by squatting deep, which is one reason why this modality is the best option for those purely interested in looking good nekkid.