Adding Barbell Displacement to Monitoring Load in the Weight Room - Worth the Effort?

OBJECTIVE
Quantifying training loads outside of practice is especially important for coaches who want to manage strength and power development. Most monitoring calculations used for monitoring load within the weight room are either volume or barbell speed, however, neither provides sufficient or precise enough information for coaches. The objective of this study was to see whether the inclusion of displacement of the barbell to the typical calculation of volume load added enough value to warrant the extra work associated with collecting the information.
WHAT THEY DID
The researchers tracked the volume load (VL) of eight national calibre weightlifters over five months using a V-scope, and a barbell displacement and tracing system which included each athlete’s loads and repetition count. To determine the volume load with the displacement (VLwD) of the barbell, a calculation of sets x repetitions x load x displacement was used at the end of the training phases. The researchers compared simple volume load and volume load with distance to see how much value barbell stroke length tracking added to the monitoring process. Pearson’s correlation coefficients were used to identify possible relationships between training variables.
WHAT THEY FOUND
The introduction of the barbell displacement measure appeared to improve the precision of the volume load calculations which suggests that its inclusion is indeed warranted and recommended for use in practice. Unfortunately, the value was only considered if time is available and the cost and extra work is likely to only be done with more coaching friendly equipment. Mechanical work is highly connected to distance with many exercises that use concentric and eccentric activities. For example, quarter squats and full range barbell squats are commonly used in training, and coaches will need exact measurements of each exercise to add more precision to their training.

Practical Takeaways
The most obvious challenge with barbell displacement is measuring it conveniently. Current technology, specifically velocity based training equipment (Review HERE), enables the path of a barbell as well as the distance it travels to be accurately measured with each rep, although some exercises can be modelled to save time. While most coaches do have a rough idea of how far displacement is with barbell exercises, objective measurement is worthwhile. The differences in precision between tall and short athletes for example, as well as styles of training can at times make it cumbersome to record exercise distance in team settings. To overcome this issue, athletes could be “fitted” during athlete screening and testing exercises so that when the athletes are prescribed workouts later the information is ready for analysis. One recommendation made by the authors of this study was to map out the exercises that are to be used before completing the session so they could be automated in excel, thus improving the monitoring process without manually recording each rep.

Carl’s Comments
“In the previous Performance Digest issue (HERE) it alluded to modelling performance and training with simple variables, one of them being leg length to give context to relative evaluation when comparing between athletes. As exercises tend to be descriptive when prescribed to athletes, coaches should tag (annotate) training based on known barbell distances, using video analysis tools such as Dartfish or Kinovea. If exercises are more variable because of athlete style, barbell tracking can be done with linear encoder devices such as Gymaware.”