Monday, February 20, 2012

Weakness Identification: Version 2.0

By Andrew McGunagle

What is the easiest way to get better at something? Identify your weaknesses and address them. In powerlifting, where getting better equates to being able to lift more weight, the formula is the same.

Addressing weaknesses is nothing new or revolutionary when it comes to powerlifting. Lifters have been deliberately targeting their weak muscle groups for many years. Furthermore, in the past couple of decades, lifters have been taking aim at weaknesses, also known as "sticking points", within their squats, benches, and deadlifts. These lifters will identify where the bar slows down or stops during a maximal attempt, and they will do various exercises that build strength in the weak areas of their range of motion. This method is effective because strength is joint angle specific; the maximal amount of force that can be exerted in a particular lift changes as a lifter moves through the range of motion and the orientation of their limbs change. This is due to various neuromuscular and biomechanical factors, but the big take away is this (quoted directly from Zatsiorsky's "Science and Practice of Strength Training"):
"Strength values at the weakest positions, or the so-called sticking points, are also very important. The heaviest weight that is lifted through a full range of joint motion cannot be greater than the strength at the weakest point."
Make sense? You cannot lift more than the amount of weight that you can lift at the weakest point of your lift. So, if you can bench 315 pounds at every joint angle except the bottom two inches, where you can only bench 295, then you are only going to bench 295. Using this simplified example, what would be the quickest way to take your bench from 295 to 315? Simply do exercises that target the bottom two inches of your bench, where you are weakest. With these thoughts in mind, let's get to the meat-and-potatoes of this article.

Weakness Identification: Version 2.0

As I alluded to previously, lifters have been been doing their best to identify the weak areas in their ranges of motion for some time now. While many lifters have done this successfully, there has to be a more precise way to do this than simply looking at a max attempt and guessing where you are weakest.

Enter, Tracker Video Analysis and Modeling Tool.

Tracker is a free computer program often used in physics courses to analyze various aspects of an object's motion. This software allows the user to select an object of interest in a video and then it can provide a bevy of information about that object's movement. What does this have to do with powerlifting? Well, all you have to do is take a video of a 1-RM lift and then designate the weight you are lifting as the object to analyze. After the analysis, Tracker can give you information about the weight's velocity and acceleration, and this information can be absolutely invaluable in guiding your upcoming training for that lift.

Before I go any further, I have to stop and give credit where credit is due. I first learned about Tracker from Mike Tuchscherer on his Reactive Training Systems website. Mike introduced the software on his forum, and he, along with a number of other lifters, helped me learn how to use the software for analyzing lifts. Much of the information that follows originated from Mike T., and I highly suggest checking out his website and his products for further information on this topic.

This stuff seems to work for Mike
Alright, getting back to Tracker and identifying weaknesses, I think that a few visual examples will be the most effective way to go about this. The following videos and analysis stills that accompany them show some old meet footage of Eric Cressey. These videos work well for analysis, as the software is more accurate when there is less camera movement and there is a consistent portion of the barbell to track.  Also, the lift has to be a maximal attempt (or as close to maximal as possible) to give relevant information.

The first video and two analysis stills shows Eric's successful second attempt deadlift with 650 pounds:
Beginning of weak ROM (about 7.5 from the start of the lift).
End of weak ROM (about 13.4 from the start of the lift).
The second video and analysis shows Eric's third attempt miss with 661 pounds:
Analysis paused at weak point (about 7.5 inches from the start of the lift).
This is where the fun begins.

In each Tracker analysis, you see two graphs. The x-axis of each graph is for the movement of the point of analysis (in this case, the barbell) in the y-direction (up and down movement). The y-axis of the top graph denotes acceleration in the y-direction, while the y-axis of the bottom graph denotes velocity in the y-direction. For each analysis, our only concern is the concentric portion of the lift in the y-direction. Movement in the x-direction (side to side movement) doesn't matter; all we are looking at is the weight as it is lifted up.

So, what Tracker does is track the weight from frame to frame in the video, and this gives information about the acceleration and the velocity of the weight. The most important information that we get comes from the weight's acceleration throughout the lift. This is due to Newton's second law of motion:

Considering that force equals mass times acceleration, and that, while lifting, the mass we are lifting is constant, we see that the force we exert during the lift depends on the bar's acceleration. So, looking at the top graph of the Tracker analysis, we look for the lowest acceleration value. The lowest acceleration value is where the lifter is producing the least amount of force. This point, where we see the lowest acceleration value(s), is the lifter's weak point. 

Remember, though, acceleration is a change in velocity (speed) of movement. So, while many lifters have mistakenly believed that their weak point is where they are slowest or where the bar gets stuck, it is actually where the bar is slowing down the most. This is an important distinction, and it highlights the power of this video analysis software. With Tracker, we can determine where the lowest acceleration is with much more accuracy than we could if we just watched the lift and guessed. Looking at the analyses of Eric's deadlifts offers an interesting example of Tracker's utility.

While there is some "noise" in the graphs, it is fairly simple to identify the weak points in Eric's deadlift. Zooming in on the acceleration graph for his 650 make, we see low acceleration values right around 0.2 on the x-axis:

While there are a couple of other low acceleration points at about 0.35 and 0.55, the value at 0.2 is notable for a couple of reasons. First, that value is followed by a couple more points of deceleration; this shows a trend of weakness in that area. Also, looking at the velocity graph, we see that this deceleration correlates with a distinct drop in velocity:

Using the diameter of the plates as a reference value, Tracker allows the user to measure and pinpoint where the weak point is. In Eric's case, his weak point is about 7.5 inches from the start of the lift (measured from where the bar is when the weight is on the ground to where the bar is at his weak point). We can also identify a weak range, which would go from that weak point at 7.5 inches all the way up to about 13.4 inches from the start of the lift. Also of note, in the second video that shows his miss, his weak point was just about at the same spot. Looking at the analysis stills, which are paused at his most prominent deceleration values, you can see that the weak point is very consistent. This leads you to believe that, if Eric had been able to produce more force at that spot 7.5 inches from the start of the lift, his velocity would not have dropped off so much and he would have had a much better chance of making that third attempt lift.

Weakness Diagnosis and Training Prescription

Without the knowledge of the relationship between force and acceleration and the ability to pinpoint the point(s) of lowest acceleration, many coaches and lifters might have advised Eric to improve his deadlift lock-out. After all, if you look at that second video, you see that he got stuck right before finishing the lift. However, this would have been an ineffective diagnosis and prescription, as the point in the range of motion that was holding Eric back was 7.5 inches off of the floor (and, looking further, he could use work from that point all the way to about 13.5 inches off the floor). If Eric could improve his ability to produce force at the point in the lift, his 1-RM would likely increase. Therefore, special exercises that would likely address this issue include pause deadlifts (with the pause occurring as close to 7.5 inches off of the floor as possible) and deadlifts where the bar is positioned 7.5 inches off of the floor (either on blocks, mats, or in a rack). The rationale behind pause deadlifts is that spending more time under tension at the weak point in the lift would influence the body to improve strength at that point. If you have never seen pause deadlifts, here is an example (fast forward to the 50 second mark; the pause in the video isn't that high, but you get the idea):


Elevated deadlifts, whether done from blocks, mats, or in the rack, force the lifter to accelerate the barbell from their weak point instead of relying on the force that is generated in the preceding range of motion. When lifting sub-maximal weights, the acceleration of the barbell can be great at the beginning of the lift, while the rest of the lift is "partially fulfilled via the barbell's kinetic energy" (Zatsiorsky). So, when training, instead of producing a lot of force at the start and coasting through his weak range, Eric would be forced to accelerate the bar from the beginning of his weak range of motion. Need an example? Konstantinovs: 

In addition, looking at the overall shape of the force (acceleration) curve gives some important information as well. Mike Tuchscherer likes to classify force curves as being more "flat/balanced" or more "wedge" shaped. However, these classifications are not black and white, as a lifter can be in between these two ends of the force curve spectrum. A flat/balanced force curve shows acceleration values hovering around zero; the lift was fairly smooth throughout. A wedge shaped force curve shows a distinct sticking point; the lifter hit a slow grinding point while the rest of the lift is fairly smooth. Looking at the analysis of Eric's deadlift, though, I would be inclined to say that his deadlift is more or less in between flat and wedge. His acceleration values hover around zero, but we do see a significant deceleration that leads to a notable drop in velocity.

For flat force curves, the lifter would focus on protocols that improve their ability to produce force. These protocols would look similar to the dynamic effort method, essentially speed and power work. The lifter would focus on sets of 1-3 reps with RPEs of 7-8. As a rule of thumb, reps should be smooth and fast when addressing a flat force curve (but that doesn't necessarily mean the weights should be "light"). 

On the opposite end of the spectrum, the standard recommendation for lifters with wedge shaped force curves include sets of moderate reps with higher RPEs. Protocols with sets of 3-5 reps with 9-10 RPEs fit the bill here. The rationale behind this type of training is that these protocols force the lifter to spend more time at their weakest joint angles. With these protocols, speed drops off as you progress towards the final reps of each set, and you are forced to grind through your weak spots. This type of training helps to strengthen the lifter's weak points while simultaneously improving their ability to grind through them.

No, not this kind of wedge.
Because Eric is more of less in between when it comes to force curve shape, we can get a little creative and use a variety of protocols. What protocols we employ and when we employ them would depend on how we choose to arrange his training cycle. However, exercise selection would aim to consistently address his weak points while maintaining a certain amount of specificity. Options include:
  • Belt-less deadlift: Earlier in the training cycle, 3-5 reps with 9-10 RPEs.
  • Competition deadlift: Transition from belt-less to competition style as competition or test date nears, protocols would be used to translate improvements from less specific exercises and protocols into sport-specific gains, low reps (1-3) with high RPEs (9-10).  
  • Pause deadlift: Throughout training cycle, pause about 7.5 inches from the start of the lift, shorter pauses (1, 2, or 3 counts) with moderate reps (2-4) early in cycle, longer pauses (5, 7, or 9 counts) with lower reps (singles) later in training cycle.
  • Elevated deadlift: Varied, elevate the bar about 7.5 inches from its normal resting point, moderate reps (3-5) and various RPEs (8-10) earlier in cycle, low reps (1-3) and higher RPEs (9-10) later in the cycle.
  • Deadlift vs. bands: Used earlier in the training cycle, 1-3 reps with 7-8 RPEs, try to set up bands so they really kick in at the weak range of motion.
Wrap Up

Identifying and addressing weak points can lead to significant improvements in your ability to lift more weight. The trick is to identify weak points accurately and then utilize targeted exercises and protocols to take care of those issues. I did my best to introduce you to a more sophisticated method of identifying weak points, but, in all honesty, I am just scratching the surface of this process. I encourage those that are interested to download Tracker and play around with it. Also, be sure to check out Mike Tuchscherer's Reactive Training Systems website, as he is offering incredibly detailed Individual Weakness Analyses and is championing this new-school analysis approach. If none of that interests you, at least remember this: Your weak point/weak range of motion is not where you are slowest or where you stop, but where you slow down the most. Identify where you slow down/stop and then work on the area slightly lower than that. That is not the most accurate method of addressing weaknesses, but it should be more effective than what most lifters are currently doing.

That's it for this week, thanks for reading! Be sure to leave any questions or comments in the comments section below or contact me at