Understanding Forces

The reference to force in this article will focus on force that isn't a byproduct of strength coupled with acceleration but rather how forces are placed upon the body during certain exercises. As we know, training can be very beneficial to anyone’s fitness or athletic goals, but understanding some of the ways in which these exercises negatively affect the body can aid in decision making in programming as well as make it easier for us as professionals to accommodate athletes and work around certain injuries.

Sheer Forces

The easiest analogy I can think of to describe sheer force is to think about whittling a piece of wood. In essence, you're sheering off the top layer of the object in an angular motion. There are certain exercises that may or may not be a part of your program that create these sheer forces. If these exercises are performed correctly, we can minimize the negative effects of these forces or keep them under control.

The following are some popular exercises that produce sheer forces:

Good mornings: Think about the way this exercise fires up your erectors and low back. This exercise is a staple in nearly every competitive powerlifter's training program and may be a necessary evil to accomplish a good power squat total. Things to keep in mind—if the athlete has a predisposition to low back injury (heredity, previous injury, anterior pelvic tilt) or if you're using this exercise to create strength in the lumbar erectors and hamstrings, it is by no means a terrible exercise. It's just a little more risky than other exercises.

To make adjustments to this exercise, try a Romanian deadlift. It's almost the same movement biomechanically, and in most instances, it allows for a greater load and cuts the sheer forces down drastically. Still having problems? Try the two for one approach. Hit the hamstring curl hard, focusing on the eccentric part of the rep, and you will get more actual hamstring stimulation, according to the EMG, and hardly any sheer force on the back. We can then couple the curls with a low back variation, 45-degree hypers, prone Supermans, glute ham back extensions, or even glute hams. Your body is at a much more disadvantaged position, and the load will never be as high as in an Romanian deadlift or good morning. Load isn't always everything (it sounds foreign to even say that). The most important aspects are muscle overloading, overcoming stress, working the muscle maximally, and adapting the muscles. I can train my posterior chain extremely hard by holding a 45-lb plate on a glute ham machine and be fried.

Leg extension: Just like the good morning, the load is placed in relation to the center point of my lever (knee joint) and dictates a high level of sheer force. This is a very popular exercise and is a great one. We just have to be careful of those injuries and predispositions before throwing these exercises into our programs. For example, post ACL surgery or acute ACL injuries are probably not good candidates for this exercise. The leg extension actually places more sheer force on the ACL than a squat. Also, this exercise places more sheer force on the patellar tendon than a parallel squat.

This exercise targets the VMO arguably better than any other exercise (huge in promoting knee stability), so any adjustments are a bit of a downgrade if this is why you're doing this exercise. A good leg press hits the VMO because a good leg press should be accommodating resistance. Pushing a sled from the backpedal position will smoke you out. With the leg extension, I prefer to keep the volume fairly low at 1–2 max sets of 8–10.

Compressive Forces

Think of stepping on a tomato. Obviously, the first exercise that comes to mind is the squat (which I love). The squatis viewed as the king of all exercises, mostly because you can hit every muscle under the bar in the squat, directly or indirectly, and it elicits the highest GH response due to the axial loading. Axial loading comes from any load that puts pressure vertically over the spine, femur, tibia, and on down.

I know most of us probably can’t think of a weekly training regimen without the squat in there at least once or twice, but sometimes you have to adjust. Think of it this way—in athletics, you're always going to have that athlete who has ridiculously long femurs coupled with some tight Achilles. You may have eight weeks to get this kid jacked, and he can’t squat 185 lbs without his form breaking down. Is he weak? Is he not trying hard? No, he is biomechanically f***ed.

Now, he can’t squat deep, and when he tries, it turns into a mixed good morning and a squat. Then you're compressing a sheering force and begging for someone to put a dumbass stamp on your head. Perception is reality in athletics. If your team looks jacked, people think your program is on point, regardless of how genetically gifted these kids are. Some of them come out of the womb yoked.

Be smart and check your ego. Believe it or not, there are other ways to get your legs and hips strong. Remember, I have eight weeks. This dude can’t squat to save his life and I need gains. Hit the leg press hard. Hit the reverse hypers and glute hams and work your adductors. I’m not sure what you're missing? I can progress up to 20 lbs a week, especially in the first micro cycle of the year (off-season) on the leg press, and I now have tangible proof that this guy got stronger.

Torque Forces

Think torque wrench. You're using a tool to place load on something in a twisting or rotational pattern. Think about what happens to your body in an exercise that has near maximal load in a rotational fashion. Some examples of exercises are rotary torso machines and land mine twists (certain variations). The rotary torso machine isn't a bad piece of equipment, but the concern is more so how it is utilized or coached. This is a great way to hit all the abdominal muscles involved in rotating the body, but there has to be particular attention paid to how you perform a rep. You have to have your core set before you initiate the rotation, so squeeze your abs to set yourself up, move without any jerking whatsoever, and keep it controlled. If I don't set my core and instead perform a relaxed jerking rep, I'm significantly increasing the chances of lumbar spine (disc) injury. Your lumbar spine isn't made for mobility. The closer you get to your butt, the less mobility is intended.

This isn't the most conventional example, but think about how we teach the bench press—tuck the elbows on the way down while ripping the bar apart, stay tight but really flare or flex the lats, and flare the elbows out away from the ribcage as you press up. In doing so, I'm experiencing compressive forces in the AC joint and torque forces around the GH fossa capsule or whatever the hell it’s called while placing sheering forces around the elbow. Just remember what athlete you're getting and what this athlete has going on within his body.

By now you're thinking, "Well, what the hell can you do in the weight room?" Accommodating around your program isn't always the easiest thing to do, but it's a necessary evil unless you're blessed with the healthiest team ever. I like and utilize most of these exercises. I will always try the squat and teach the squat intensely for quite a few sessions in a row, but I just don’t have the time to let gains go by the wayside. The bottom line is we all have to make sure we understand to a certain degree how the body works, how certain exercises affect the body, and what to do when an exercise isn't the best choice for an athlete. If we have too much of an ego and put our exercise selection in front of our athletes' physical well-being, we're doing them absolutely no good and may potentially injure them. I definitely don't know everything about injury prevention (if there is such a thing) or dealing with every injury, but I absolutely feel that this topic should stay in focus when we're dealing with athletes.