By Carl Valle
The current practice of using barbell speed measurements in the weight room is at a critical mass. Several pioneers in applied sport science and the coaching profession have moved the needle significantly, for both elite athletes and gym rats, with practical research and cutting-edge methodology. While Velocity Based Training (VBT) is a major factor in training the primary lifts, it’s the tip of the iceberg with what can be done by using comprehensive barbell analysis.
Bar speed—peak or average—is vital in improving training outcomes. Adding more of the right information can break through barriers and increase the precision of any program. In this article, we will explore the hidden factors in key exercises for lower body power and share ways to look at the data more intelligently. Besides analysis, we also suggest adjustments with small tweaks. Athletes at any level can reap more rewards by diving into bar trajectory metrics.
Barbell Trajectory Sport Science
What is the definition of barbell trajectory, and what does it offer someone beyond the two popular bar speed metrics of peak and average? One can make a case that 2015 was the year of VBT. If this article does its job, 2016 could be the year of BTA (Bar Trajectory Analysis). The big picture of barbell analysis is essential to maximizing training time and effort. Those who want to stay comfortable by looking at intermediate feedback of gross bar speed are missing the following:
- Bar displacement – The sum of the entire distance the bar travels from start to finish of the lift.
- Bar activity duration – The sum of the entire time of the exercise performed. This score can include the accessory motion of the liftoff and other small contributions to the exercise that many forget. For purposes of education, the exercise performance will be used in this working definition.
- Bar directional measures – The contributing bar motion in space from the start to the end of the exercise.
- Bar relative measures – The relationship between the bar motion path in the exercise and the body anthropometry of the performer.
Take note—these four metrics are not all that can be done with barbell analysis, but trying to swallow too much often overloads coaches and is overkill for those doing an honest job with athletes. A simple way of looking at less common measures is thinking in terms of the context of the bar speed at which one is usually training. Bar speed is simply a snapshot of a moment in time, not the complete picture of what is going on. Bryan Mann’s work gave coaches a working understanding of how different exercises can be evaluated. It was never intended as a road map, but more a compass for speed to orient everyone. Bar trajectory may be viewed as the route and scale on a nautical map. The coach is the captain of the ship in this analogy, and may change course along the way based on wind and weather.
These four metrics are foundational. Using them as a framework can help anyone perform popular lifts better. Nothing in technology will replace coaching, but not using technology that provides objective data is egotistical and retards the progress of sports training. Here are some real-world examples to help illustrate these metrics in applied training settings.
How Bar Displacement Influences Bar Velocity
The total straight distance the barbell travels—mainly vertically overcoming gravity—is a major reason bar velocity can be deceptive if not interpreted correctly. How much distance athletes have to work with determines what they can generate with regards to bar speed. “Impulse” is perhaps a better word for coaches, but the clarity of how far the bar travels and in what way is important to convey. One example that anyone who performs the snatch in various forms can relate to is modifying starting position and grip. These changes can create a significant change in bar velocity without actually indicating an improvement or loss of power ability.
Photogrammetry in the early 1970s used film and smart math to extract information. Similar to Muybridge proving that horses had all four legs off the ground simultaneously, photos at high shutter rates explained how champions executed their winning performances. The perception of the barbell path as a straight line to the naked eye was indeed inaccurate. The bar moved slightly away from the lifter.
Another revolutionary leap with sport science began in the mid-1980s as computers became real tools for greater insight. Swedish sport scientists mapped out bar trajectory metrics at the 1985 World Championships in Weightlifting. They analyzed both horizontal (minimal) and vertical motion with amazing precision. They traced the bar path, and the actual distance of the bar was longer than the maximal vertical displacement. What can get tricky is the understanding that distance traveled and displacement are not synonymous. A 400m runner travels about a quarter mile and winds up virtually back at the starting point.
In weight training, the key is breaking down the total distance traveled and the starting and finishing positions for smarter evaluation. Most motions are not perfectly straight lines from point A to point B, so focus on what is accepted as technically proficient in the literature. Most athletes find success by improving the output of the lifts through coaching and better programming.
Why Bar Duration Matters for Nervous System Fatigue
The fatigue rate of muscle contractions is not crystal clear in the scientific literature, but a general summary of short explosive bursts as the best approach to developing power is a fair conclusion. General duration—regardless of how far the bar moves—is a safe bet in getting more output with less risk of unnecessary fatigue. The bar distance, direction, and duration or time traveled give context to bar speed. For example, the deadlift is very effective but comes with a price to pay later. The key reason is that heavy deadlifts performed without wide stances take a long time to complete.
A clear relationship exists between mean and peak power/velocity and lift duration. A slow motion simply takes more time to perform, and high-velocity movements (all else being equal) take less time. Powerlifting and Olympic weightlifting are about the greatest possible loads. Usually, the time of the rep of Olympic movements stays close to the lighter loads, while power lifts vary speeds more. Fatigue is a normal and essential part of training, but only when one can adapt to it. Otherwise, it’s unnecessary “overflow” or residual exhaustion. The return of cluster sets for greater outputs is coming back in a full circle as they increase output, and it’s up to coaches to see how they can weave them into seasonal training plans.
We currently don’t know the intimate details of why central and peripheral fatigue alter strength, speed, and power training. We do know that the explosive motor units in Type II fibers can be burned out from work that involves high effort and long duration. In the future, it will be up to sport scientists to collaborate with real training programs to discover what happens and how coaches can improve results and minimize errors.
Bar Directional Measures and Neuromuscular Adaptations
Concentric and eccentric actions are not new, and we are starting to see how simple muscle contractions are not just lengthening and shortening. The key point with barbell tracking is that velocity is constantly changing, and the direction the bar travels is dangerously underappreciated. The gradual collapse of the athlete health in sport is frightening because of the fears of overtraining. Muscle soreness, a subjective monitoring point in muscle damage estimation, is overly relied on and inflated from an aversion to strength training.
A vicious cycle of injury and lack of training continues as most programs classify exercises based solely on anatomy versus important factors like neural response and, in this case, eccentric contractile dynamics. A hexagonal deadlift does induce muscle recruitment to the posterior chain, but most athletes drop the weight rapidly with gravity versus resisting it. Eccentric qualities must constantly be under surveillance. Otherwise, it’s easy to get into a program that doesn’t improve the ability to yield.
One excellent example of bar direction making a difference is the receiving point and distance of competitive lifts versus sport preparation options. The power clean and power snatch with a squatting pattern finish are different than catching the bar lower with a shallow descent.
Bar Relative Measures and Body Types
Athlete anthropometry is a major variable in performing the lifts and interpreting their performance. While barbell and plates are standardized, athletes’ bodies come in many different shapes and sizes. Style of execution must also be considered. A narrow-grip bench press by a developing college power forward is much different than a traditional grip by a short veteran NFL running back.
Coaches and athletes can look at bar velocity more intelligently by considering bar load, body weight and composition, and effort. Load and bar speed are related to the weight of the athlete, readiness to train, motivation, and effort. Larger athletes are usually taller as well, so higher speeds may not be due to power, just the amount of available time.
Rate of force production (RFD) is an emerging metric with bar velocity tracking, but the concept is far from new. The primary issue with RFD is that measurement is hard to define specifically with exercises and is very sensitive. RFD is inappropriately perceived as explosive starting power, as most exercises from the floor or a static start are prone to protocol inconsistency and mechanics of the lift. Examples are jump squats with variable starting leg joint positions or not adhering to rest periods. Other examples are the style of cleans or snatches that may have slower starting speeds to favor the second pull or athletes with less mechanically advantageous positions due to anthropometric factors. Finally, RFD is based on a time interval in milliseconds, so it’s wise to observe peak velocity to ensure that the numbers are valid. This doesn’t mean RFD is a poor metric. It just points out the need for interpretation and being privy to the context of the data collected.
Getting Started Now With Bar Trajectory
This article explains major contributing factors in improving performance in the granddaddy exercises and adds more value to preexisting measures of peak and mean velocity. The next logical question is what can be done with bar velocity and power indices of the GymAware system and assisting those scores with in-depth analysis.
After collecting the data, the numbers will spark change and shed light on what is holding one back. Every athlete and every movement are unique enough to require an individualized process that teases out what is sensible and what likely needs to be improved. Most people in the iron game can decode the data by simply seeing it, not by sending the numbers to a data scientist or uploading the file to powerful software. What has worked for many coaches and athletes is identifying the problem by profiling the pattern of the movement they want to improve and then engineering ways to augment the performance with hard work and patience.
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Suggested Reading
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González-Badillo JJ, Sánchez-Medina L. “Movement velocity as a measure of loading intensity in resistance training.” Int J Sports Med 31: 347–352, 2010.
Harbili E, Alptekin A. “Comparative kinematic analysis of the snatch lifts in elite male adolescent weightlifters.” J Sports Sci Med 13: 417–422, 2014.
Pareja-Blanco F, Rodríguez-Rosell D, Sánchez-Medina L, Gorostiaga EM, González-Badillo JJ. “Effect of movement velocity during resistance training on neuromuscular performance.” Int J Sports Med 35: 916–924, 2014.
Oliver JM, Kreutzer A, Jenke SC, Phillips MD, Mitchell JB, Jones MT. “Velocity drives greater power observed during back squat using cluster sets.” J Strength Cond Res, 2015. Epub Ahead of Print.
Cronin JB, McNair PJ, Marshall RN. Force-velocity analysis of strength-training techniques and load: Implications for training strategy and research. J Strength Cond Res 17: 148–155, 2003.
Baumann W, Gross V, Quade K, Galbierz P, and Schvvirtz A. The Snatch Technique of World Class Weightlifiers at the 1985 World Championships Int J Sport Bio 4;68-89, 1988
