Sled-Pull Load–Velocity Profiling and Implications for Sprint Training Prescription in Young Male Athletes

Abstract

The purpose of this study was to examine the usefulness of individual load–velocity profiles and the between-athlete variation using the decrement in maximal velocity (Vdec) approach to prescribe training loads in resisted sled pulling in young athletes. Seventy high school, team sport, male athletes (age 16.7 ± 0.8 years) were recruited for the study. All participants performed one un-resisted and four resisted sled-pull sprints with incremental resistance of 20% BM. Maximal velocity was measured with a radar gun during each sprint and the load–velocity relationship established for each participant. A subset of 15 participants was used to examine the reliability of sled pulling on three separate occasions. For all individual participants, the load–velocity relationship was highly linear (r > 0.95). The slope of the load–velocity relationship was found to be reliable (coefficient of variation (CV) = 3.1%), with the loads that caused a decrement in velocity of 10, 25, 50, and 75% also found to be reliable (CVs = <5%). However, there was a large between-participant variation (95% confidence intervals (CIs)) in the load that caused a given Vdec, with loads of 14–21% body mass (% BM) causing a Vdec of 10%, 36–53% BM causing a Vdec of 25%, 71–107% BM causing a Vdec of 50%, and 107–160% BM causing a Vdec of 75%. The Vdec method can be reliably used to prescribe sled-pulling loads in young athletes, but practitioners should be aware that the load required to cause a given Vdec is highly individualized.

Influence of resisted sled‐push training on the sprint force‐velocity profile of male high school athletes

“…All participants were familiarized with the equipment and testing procedures 1 week prior to data collection by performing two maximal effort repetitions at loads corresponding to light, moderate, and heavy. Load‐velocity profiling and prescription of loads was conducted using unresisted and resisted trials as described by Cahill et al A radar device (Model; Stalker ATS II, Applied Concepts, Dallas, TX, USA) was positioned 10 m directly behind the starting position to determine the maximum velocity (Vmax) of both unresisted and resisted trials. The range of selected loads at increments of 20% was based on pilot testing that reduced an athletes velocity by values above and below 50% of unresisted Vmax.…”

“…Although sled pushing is viewed as a similar method to sled pulling, many differences exist (eg, size, shape, friction, and anterior positional orientation of the sled) which likely result in unique kinematic and kinetic changes . Only one study exists on resisted sled pushing in young athletes and although it found the prescription of load reliable for post‐peak height velocity (PHV) athletes; a greater degree of between‐participant variability in load was found in sled pushing in comparison with sled pulling when reported as the percentage of body mass (%BM) required to cause a given decrement in velocity . The most notable difference between push and pull conditions is the use of the arms to directly apply force onto the sled device and overcome momentum during the initial first step of the sprint is unique to sled pushing.…”

“…The most notable difference between push and pull conditions is the use of the arms to directly apply force onto the sled device and overcome momentum during the initial first step of the sprint is unique to sled pushing. Therefore, sled pushing should be viewed as a unique and specialized form of horizontal resistance training …”

“…While research using the method is relatively uncommon, sled pushing has been examined in relation to post‐activation potentiation and blood lactate response in adults in which relatively heavy loading parameters were used . A recent study by Cahill et al examined the reliability and variability within sled pushing concluding that loads can be reliably prescribed to young athletes, with the caveat that the loading response is highly individualized. However, there is a paucity of longitudinal research examining the effectiveness of sled pushing in improving sprint performance.…”

“…This method uses the known linear relationships between force and velocity and load and velocity, which have been shown to exist for sled pulling and more recently, sled pushing . Cahill et al suggested light, moderate, and heavy loading parameters at sled pushing loads corresponding to 25%, 50%, and 75% Vdec to represent speed‐strength, power, and strength‐speed zones, respectively, but further research is needed to confirm the effectiveness of training within these zones. Categorizing sled pushing as a horizontal strength training exercise might suggest that training would be most effective at heavier loads, particularly with young athletes where there is a large potential to develop force production .…”