Reliability of the Maximal Resisted Sprint Load Test and Relationships With Performance Measures and Anthropometric Profile in Female Field Sport Athletes

Abstract

Resisted sled sprint (RSS) training is an effective modality for the improvement of linear sprint speed. Previous methods of RSS load prescription e.g. an absolute load or as a percentage of body mass (%BM), do not account for inter-individual differences in strength, power or speed characteristics, although the 'maximum resisted sled load' (MRSL) method of RSS load prescription may provide a solution. MRSL is defined as the final RSS load before an athlete can no longer accelerate between two phases (10-15 m and 15-20 m) of a 20 m linear sprint. However, the MRSL test has not been analysed for reliability. Additionally, MRSL performance has not been compared to the outcome of other performance tests. The primary aim of this study was to investigate the reliability of the MRSL testing protocol in female field sport athletes. Participants (age, 20.8 ± 1.9 y; body mass, 64.3 ± 8.4 kg; height, 1.66 ± 0.65 m) tested for anthropometric measurements, strength and power performance testing and twice for MRSL. MRSL values ranged from 20.7 to 58.9%BM. MRSL test-retest reliability intraclass correlation coefficient, confidence intervals and coefficient of variations were 0.95, 0.85-0.98 and 7.6%, respectively. MRSL was 'moderately' and 'strongly' correlated with a number of anthropometric and performance tests (p < 0.05) including % fat free mass, countermovement jump, loaded countermovement jump, rate of force development, horizontal jump and horizontal bound performance. MRSL is a reliable measure for determining the RSS load at which an individual can no longer accelerate during a single RSS effort over 0-20 m. MRSL also accounts for inter-individual variation in body composition, power and speed characteristics of female field sport players.

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

“…Reliability analysis demonstrated no systematic bias in any of the variables, suggesting the absence of any learning effects, which is in agreement with previous research in adult populations [5,9,16]. This is the first study to examine the reliability of resisted sled pulling in young athletes.…”

“…The high degree of reliability shown in the current study are congruent with previous research examining sled load prescription [5,16]. The lack of systematic bias and stable random variation across trials suggests there were no improvements in reliability across trials, which may be partly due to the familiarization to sled pulling prior to data collection.…”

“…A popular method of sprint-specific training is to add resistance while moving in a horizontal plane of motion, commonly referred to as resisted sprint. Recently, researchers have focused on resisted sled sprinting, specifically sled pulling, as a popular and effective method of sprint training [5,6]. As with traditional resistance training, the resistive load used during sled pulling needs to be appropriately prescribed to cause the desired training adaptations.…”

“…The majority of previous sled pulling research has been studied in adult populations and has prescribed lighter loads (<30% body mass) with the emphasis on ensuring minimal disruption in sprint mechanics and small acute reductions in speed [7,8]. The reliability of resisted sled sprinting has been studied in adult populations [5]. However, the reliability across multiple loads from light to heavy has not been examined in young athletes.…”

Current perceptions of strength and conditioning coaches use of sled tow training

“…The significant variance has been shown in adults, and to a greater extent in youth athletes, in which the load required to provide a 50% decrement in maximal sprinting speed almost doubles between athletes who tolerate load the least to those who tolerate load the most when expressed as a % BM during ST. 5,6 Consequently, more qualitative methods of sled load prescription have been suggested to individualize training and minimize the between- athlete variation, such as assessing the velocity decrement (V dec ) caused from sled loading from one’s maximal speed. 6,7 Force-velocity profiling (FV) during unresisted sprinting can offer the coach valuable insights into the individual characteristics of each athlete and how to individualize load specific to their force or velocity dominancy. Specific to sled towing, sprint phase adaptation is related to the resistive stimulus, with heavier loads eliciting greatest gains in early acceleration, and lighter loads or unresisted sprinting benefiting the latter phases and maximal velocity.…”