Know How to Prepare Your Legs for a Bout
By Bob LeFavi, PhD, CSCS, CHES
In your conditioning for BJJ you may spend a good bit of time training your upper body. And why not, that’s where so much upper body strength and power is needed in your ground game.
However, those in BJJ – a sport where athletes not only support themselves but also others – can sometimes fail to appreciate how physically taxing a bout can be on lower body musculature. Fact is, it is the muscles of the lower body that help stabilize a fighter throughout a bout. If you are one of those who could use an update on how to train legs for optimal BJJ performance, read on.
The first step in intelligent leg training is to know which exercises really work which muscles and how to perform these exercises for maximum results. While there are many different exercises that train legs, I’ll stick with the three most popular compound, multi-joint exercises: the leg press, the hack squat, and the squat itself. Other cutting edge articles on this website will focus on more kinetic, plyometric and sport specific exercises, but there is no question that more leg strength and power has been developed with the exercises discussed below than all other leg exercises combined.
All three are similar in that flexion (see box on Leg Training Terms) and extension occur at the hip and knee, while plantar flexion and dorsi flexion occur at the ankle. But, do all three exercises yield similar results? Let’s look at the biomechanical and muscular involvement factors associated with each exercise.
The hack squat involves a quadriceps-dominated contraction, with minimal hamstring involvement. Hacks are a great exercise for quadriceps development, but not much else. With training legs, like any other body part, you should determine the areas of the muscle or muscle group that need improvement and do everything possible to stress those areas with your training.
As your kick weakens, where is the weakness coming from? If you are losing strength and power from your hamstrings and/or glutes, then your time would be better spent with another leg mass builder. This is not to say that hacks are not a good exercise; they are, but mostly for developing your quadriceps.
Here’s where things can get a little sticky. The leg press also produces a quadriceps-dominated contraction, with very little hamstring involvement unless a radical foot placement is used. Typically in an effort to stress the hamstrings, lifters place their feet very high on the footplate, sometimes with only their heels making contact. (Of course, they lower their feet on the platform to shift the resistance forward, emphasizing quad involvement). This decreases the stress on the quadriceps, and may appear to add stress to the hams. Let’s take a closer look at this.
Various foot positions change the stress on various muscle groups
For the most part, the hamstrings cross the hip and knee joint (the exception being the short head of biceps femoris which only crosses the knee). The hams have two functions: (1) to flex the knee joint, and (2) to extend the hip joint. The hamstrings also aid the glutes with hip extension, which is why the hams are stressed in the stiff-legged deadlift – a hip movement.
During the leg press, the quadriceps eccentrically control the motions of knee flexion and hip flexion, and concentrically control hip and knee extension. Wilk et al. in 1996 examined electromyographical (EMG) activity of the muscles in the leg with various open and closed chain exercises (see box on OKC and CKC exercises). He found no evidence of quadriceps/hamstring co-contraction (both muscles groups being stimulated) during the horizontal leg press, a body position very similar to the hack squat.
Wilk theorized that the hamstrings contracted in response to trunk position relative to the knee. That is, when the upper body moves forward toward the knees in the exercise, the hams and glutes, due to the forward flexion needed at the hip, become more involved.
Now with the 45-degree leg press (the one you are most likely to use), the trunk is definitely over the knees, but is also stationary and supported by the seat. Therefore, no forward flexion at the trunk occurs; you can’t move your upper body forward like you have to in the squat.
Hamstring and glute involvement is minimal because no trunk control is needed, thereby minimizing the required force of the hamstring contraction (the quads are doing most of the work). Sure, the hams and glutes are shortening during the movement, but little contractile force is necessary, so little muscular adaptation occurs.
The squat is, without a doubt, the king of leg exercises. During the squat, both the quadriceps and hamstrings are heavily involved, as are the glutes. The squat involves the hamstrings and glutes in hip extension (here, with significant involvement), and in controlling and changing the position of the trunk.
During the descent phase, the hamstrings and glutes contract eccentrically to control the forward movements of the trunk that occur during hip flexion. In the ascent phase, these muscles contract concentrically to extend the hip and trunk with some help from the lumbar paraspinals. Both Wilk et al. and Ninos et al. have done recent studies that confirm the involvement of the hamstrings during the squat.
The squat has other benefits unique to it. Many muscles not directly involved in the squat have to work isometrically in order to stabilize the body and the bar. Trapezius and rhomboids work isometrically to control the bar, your abdominals work to increase intra-abdominal pressure to help support the spine (your small spinal stabilizers also aid with this), the paraspinals contract isometrically to keep the spine in extension, and so on and so on. In fact, approximately 240 different muscles are contracting in some way during the squat.
All this stabilization work performed in addition to the concentric/eccentric work performed to actually lift the weight is why squats are so taxing. There is a high metabolic cost to squatting; no wonder you feel like puking sometimes! Squats develop the quads, hams and glutes; this cannot be said for hack squats or leg presses to the same degree.
I hear many in the gym say, “Squats are bad for your knees, so I don’t do them.” This just isn’t so. Robert Panariello examined the effect of full squats on knee stability in 1994 and concluded that full squats were a safe exercise for athletes with normal knees. Even athletes that have undergone surgical procedures for knee injuries can and often do return to squatting with no trouble.
Squatting is also an integral part of many lower extremity rehabilitation protocols. In short, many people don’t squat ’cause it’s too darn hard. As a BJJ athlete, you are afraid of “hard.”
The rewards of squatting outweigh any temporary discomfort caused by them. Worrell et al. reported significant improvement in functional activities after a four-week lateral step up protocol. These included a one-leg hop for distance and one-leg hop test for time. The lateral step up closely resembles a one-leg squat and would involve the same muscles, but not be as strenuous.
Conversely, in 1996, Wawrzyniak et al. tested the effect a six-week leg press training protocol had on quadriceps strength and functional test improvement. This study revealed that while the quadriceps increased in strength, there was no carryover in terms of functional improvement as measured by the two hop tests (distance and time).
We believe this is due to the fact that during athletics as well as other functional activities, the quadriceps and hamstrings work together (co-contract), and this co-contraction is enhanced by activities like squats and step-ups. Anyone interested in maximizing sports performance should be aware of the unique muscular involvement differences in many multi-joint movements.
Not all closed chain activities are created equal. Know what is affected by the exercises you choose.
DEPTH OF MOVEMENT
We’ve all seen the lifters who make a habit of loading up a squat bar or leg press, and those who are barely able to stand while performing several sets of quarter squats. Would you habitually do partial curls for your biceps? Complete range of motion is vital for full muscular development. Partials are fine if done correctly and if done as an adjunct to regular training. Full range movements should be the core of any training program to achieve maximum results.
Research has indicated that peak quadriceps activity occurs at 93-113 degrees of knee flexion during the leg press. The leg press study conducted by Wawrzyniak revealed that quadriceps strength increased to a significantly greater degree when the leg press was performed from 0-90 degrees of knee flexion versus 0-60 degrees of flexion. The point is: Full squats are safe when performed properly and offer tremendous benefits over the leg press and hack squat.
THE BOTTOM LINE
Say it any way you want, but the bottom line in the gym has always been and continues to be the oft-quoted phrase, “knowledge is power.” It enables you to bring up weak points and use training variety intelligently.
By learning more about lower extremity structure, biomechanics and function, you can develop the tools you need to design a leg training program that’s right for you!
VARIATIONS OF THE SQUAT
The squat has many variations, each with it’s own unique attributes. Keep in mind what happens to the line of force as the resistance is moved in certain exercise variations. Specifically, the line of force will shift forward on your body (toward your chest instead of your back), meaning that you’ll activate the quads more than their antagonists, anytime you perform some of the more common variations:
High Bar Squats
The bar is placed high on the trapezius, very close to the neck and a more upright posture of the torso is maintained. This more upright position decreases trunk lean, thereby maximizing quadriceps stimulation and reducing the stress on the hamstrings and glutes. This variation does stimulate the hamstrings and glutes, just not to the same degree as power squats.
The goal of the power squat is to position the bar on the back to maximize leverage and lift as much weight as possible. This is done by placing the bar along the top of the rear deltoids and below the upper traps. Here, the weight is over the heels, compared to being over the mid-foot as in the high bar squat. (Not only did the weight drop on the back, but also moved to the rear.)
This placement causes the lifter to flex more at the hip in order to control the weight. The power squat utilizes the glutes, hamstrings, and erector spinae to a much greater degree than high bar squats and is the best choice for increasing overall strength, power and athletic performance.
Front squats, where the bar is moved to the front of the body and held near the clavicle, represents perhaps the most drastic forward shift of the line of force possible in a squat exercise. This exercise affects the quadriceps in a major way, but doesn’t really do much of anything else. This is due to the position of the weight relative to the torso. The torso remains upright throughout the movement so the contribution of the glutes and hamstrings is minimal.
It doesn’t take a Rhodes scholar to see how well this maneuver works at developing the frontal thigh. Just look at the huge quads of Olympic-style weightlifters; they use a front squat to come out of the hole in a clean and jerk.
This exercise, with a small block or plate under your heels, propels lifters forward and forces them to drive more through the ball of their feet instead of through flat feet. To counteract this, they must consciously try to maintain an upright trunk position, thus placing more of the resistance on their quads, reducing the load on the hams, glutes and lower back.
The placement of the feet can also affect which muscles are involved. A close stance will limit hip flexion, and is commonly used with the high bar squats. A wide or medium stance allows for maximum hip flexion and also strongly involves the adductors (inner thigh muscles) as stabilizers. A medium-width stance is recommended for power squats to maximize the involvement of all muscle groups.
Leg Training Terms
These terms are defined as they apply to training the lower extremities.
Flexion at the hip occurs when the angle between the thigh and abdomen decreases, or when the thigh approaches the abdominals. Flexion at the knee occurs when the angle between the calf and thigh decreases, or when the calf approaches the hamstring. An example of both hip and knee flexion is the decent or eccentric phase of the squat.
Angle between shin and toes increases, as in the ascent phase of the squat. Also, the starting position of the ankle in a heel-raised squat is plantar flexed.
Angle between shin and toes decreases, as in the descent phase of the squat. You need strong dorsi-flexors to keep your feet locked and hold someone in guard. Heel walking can strengthen these muscles.
Co-contraction occurs when the muscles around a joint contract simultaneously to provide stability. During the squat, the head of the femur (thigh bone) rotates inside the acetabulum (socket) of the pelvis while the acetabulum rotates around the head of the femur. Whew!
What’s the point? Both parts of the joint are moving at the same time creating an unstable situation, thus necessitating a co-contraction. This simultaneous movement does not occur during leg press as only head of the femur is moving; the pelvis is stable. (Again, this is the reason the hams and glutes are not involved to a great extent in the leg press).
Most lifters aren’t aware of co-contraction, nor do they desire it. Bodybuilders usually focus on one muscle group at a time and want to “isolate” it. With the lower extremities, that’s a difficult task since so many joint are moving at one time. Even if it’s not optimal, at least be knowledgeable about which exercises are bringing in which muscle groups.
Also referred to as compound movements, involve movement at more than one joint at the same time. Squats involve movement at the hip, knee, and ankle, as do leg press and hack squats. However, all multi-joint movements are not created equal.
An attempt by the muscle to shorten when the force it can produce is greater than the resistance it has encountered; a shortening contraction.
A lengthening contraction (i.e., the quads in the descent phase of the squat).
To achieve optimal stimulation of the quadriceps you have to go deep. Studies have shown that maximal quadriceps activity occurs at 93-113 degrees of knee flexion; that’s at least parallel if you’re doing a power squat. Studies have also shown that if done correctly, deep squats are not harmful to the knees.
OKC and CKC Exercises
Question: What is the leg exercise that creates the most vulnerability to the knee? Nope, not squats – leg extensions! And no, I’m not kidding.
You see, leg extensions are an open kinetic chain (OKC) exercise. OKC movements involve motions where the end of the limb is not fixed and is freely movable, such as the arm in throwing motions and the leg in kicking, running and knee extension (the biomechanically correct term for the leg extension exercise) motions. These movements typically are single-joint motions, utilize a limited number of muscle groups, and are referred to as isolation exercises.
Closed kinetic chain (CKC) movements involve motions where the end of the limb is fixed and stable, such as squats and leg presses. CKC movements are generally multi-joint movements, calling into play many muscle groups to act as stabilizers and antagonists during the motion.
Believe it or not, because leg extensions, as an OKC movement, involve shear forces and not compressive forces, are potentially able to improperly track the tibia in relation to the femur, overwhelmingly stress the anterior cruciate ligament (ACL), and do not bring in co-contractors, most sports therapists believe them to more dangerous than squats (or any motion utilizing fixed feet).
1. Ninos, JC, J.J. Irrgang, R. Burdett, and JR Weiss. Electromyographical analysis of the squat performed in self-selected lower extremity neutral rotation and 30o of lower extremity turn-out from the self-selected neutral position. Journal of Orthopaedic and Sports Physical Therapy 25(5):307-315, 1997.
2. Panariello, RA, SI Backus, and JW Parker. The effect of the squat exercise on anterior-posterior knee translation in professional football players. American Journal of Sports Medicine 22(6):768-773, 1994.
3. Wilk, KE, RF Escamilla, GS Fleisig, SW Barrentine, JR Andrews, and ML Boyd. A comparison of tibiofemoral joint forces and electromyographical activity during open and closed kinetic chain exercises. American Journal of Sports Medicine 24(4):518-527, 1996.
4. Wawrzyniak, JR, JE Tracy, PV Catizone, and RR Storrow. Effect of closed chain exercise on quadriceps femoris peak torque and functional performance. Journal of Athletic Training 31(4):335-340, 1996.
Dr. Bob LeFavi, Certified Strength and Conditioning Specialist, is Professor in the College of Health Professions, Armstrong Atlantic State University, Savannah, GA.