Robert G. Lockie

Factors that differentiate acceleration ability in field sport athletes.

Lockie, RG, Murphy, AJ, Knight, TJ, and Janse de Jonge, XAK. Factors that differentiate acceleration ability in field sport athletes. J Strength Cond Res 25(10): 2704–2714, 2011—Speed and acceleration are essential for field sport athletes. However, the mechanical factors important for field sport acceleration have not been established in the scientific literature. The purpose of this study was to determine the biomechanical and performance factors that differentiate sprint acceleration ability in field sport athletes. Twenty men completed sprint tests for biomechanical analysis and tests of power, strength, and leg stiffness. The sprint intervals analyzed were 0–5, 5–10, and 0–10 m. The subjects were split into a faster and slower group based on 0- to 10-m velocity. A 1-way analysis of variance determined variables that significantly (p ≤ 0.05) distinguished between faster and slower acceleration. All subject data were then pooled for a correlation analysis to determine factors contributing most to acceleration. The results showed that 0- to 5-m (∼16% difference) and 0- to 10-m (∼11% difference) contact times for the faster group were significantly lower. Times to peak vertical and horizontal force during ground contact were lower for the faster group. This was associated with the reduced support times achieved by faster accelerators and their ability to generate force quickly. Ground contact force profiles during initial acceleration are useful discriminators of sprint performance in field sport athletes. For the strength and power measures, the faster group demonstrated a 14% greater countermovement jump and 48% greater reactive strength index. Significant correlations were found between velocity (0–5, 5–10, and 0–10 m) and most strength and power measures. The novel finding of this study is that training programs directed toward improving field sport sprint acceleration should aim to reduce contact time and improve ground force efficiency. It is important that even during the short sprints required for field sports, practitioners focus on good technique with short contact times.

The effects of different speed training protocols on sprint acceleration kinematics and muscle strength and power in field sport athletes.

Abstract Lockie, RG, Murphy, AJ, Schultz, AB, Knight, TJ, and Janse de Jonge, XAK. The effects of different speed training protocols on sprint acceleration kinematics and muscle strength and power in field sport athletes. J Strength Cond Res 26(6): 1539–1550, 2012—A variety of resistance training interventions are used to improve field sport acceleration (e.g., free sprinting, weights, plyometrics, resisted sprinting). The effects these protocols have on acceleration performance and components of sprint technique have not been clearly defined in the literature. This study assessed 4 common protocols (free sprint training [FST], weight training [WT], plyometric training [PT], and resisted sprint training [RST]) for changes in acceleration kinematics, power, and strength in field sport athletes. Thirty-five men were divided into 4 groups (FST: n = 9; WT: n = 8; PT: n = 9; RST: n = 9) matched for 10-m velocity. Training involved two 60-minute sessions per week for 6 weeks. After the interventions, paired-sample t-tests identified significant (p ⩽ 0.05) within-group changes. All the groups increased the 0- to 5-m and 0- to 10-m velocity by 9–10%. The WT and PT groups increased the 5- to 10-m velocity by approximately 10%. All the groups increased step length for all distance intervals. The FST group decreased 0- to 5-m flight time and step frequency in all intervals and increased 0- to 5-m and 0- to 10-m contact time. Power and strength adaptations were protocol specific. The FST group improved horizontal power as measured by a 5-bound test. The FST, PT, and RST groups all improved reactive strength index derived from a 40-cm drop jump, indicating enhanced muscle stretch-shortening capacity during rebound from impacts. The WT group increased absolute and relative strength measured by a 3-repetition maximum squat by approximately 15%. Step length was the major limiting sprint performance factor for the athletes in this study. Correctly administered, each training protocol can be effective in improving acceleration. To increase step length and improve acceleration, field sport athletes should develop specific horizontal and reactive power.

Relationship between unilateral jumping ability and asymmetry on multidirectional speed in team-sport athletes.

Abstract Lockie, RG, Callaghan, SJ, Berry, SP, Cooke, ERA, Jordan, CA, Luczo, TM, and Jeffriess, MD. Relationship between unilateral jumping ability and asymmetry on multidirectional speed in team-sport athletes. J Strength Cond Res 28(12): 3557–3566, 2014—The influence of unilateral jump performance, and between-leg asymmetries, on multidirectional speed has not been widely researched. This study analyzed how speed was related to unilateral jumping. Multidirectional speed was measured by 20-m sprint (0–5, 0–10, 0–20-m intervals), left- and right-leg turn 505, and modified T-test performance. Unilateral jump performance, and between-leg asymmetries, was measured by vertical (VJ), standing broad (SBJ), and lateral (LJ) jumping. Thirty male team-sport athletes (age = 22.60 ± 3.86 years; height = 1.80 ± 0.07 m; mass = 79.03 ± 12.26 kilograms) were recruited. Pearsons correlations (r) determined speed and jump performance relationships; stepwise regression ascertained jump predictors of speed (p ⩽ 0.05). Subjects were divided into lesser and greater asymmetry groups from each jump condition. A 1-way analysis of variance found between-group differences (p ⩽ 0.05). Left-leg VJ correlated with the 0–10 and 0–20-m intervals (r = −0.437 to −0.486). Right-leg VJ correlated with all sprint intervals and the T-test (r = −0.380 to −0.512). Left-leg SBJ and LJ correlated with all tests (r = −0.370 to −0.729). Right-leg SBJ and LJ related to all except the left-leg turn 505 (r = −0.415 to −0.650). Left-leg SBJ predicted the 20-m sprint. Left-leg LJ predicted the 505 and T-test. Regardless of the asymmetry used to form groups, no differences in speed were established. Horizontal and LJ performance related to multidirectional speed. Athletes with asymmetries similar to this study (VJ = ∼10%; SBJ = ∼3%; LJ = ∼5%) should not experience speed detriments.

A preliminary investigation into the relationship between functional movement screen scores and athletic physical performance in female team sport athletes

There is little research investigating relationships between the Functional Movement Screen (FMS) and athletic performance in female athletes. This study analyzed the relationships between FMS (deep squat; hurdle step [HS]; in-line lunge [ILL]; shoulder mobility; active straight-leg raise [ASLR]; trunk stability push-up; rotary stability) scores, and performance tests (bilateral and unilateral sit-and-reach [flexibility]; 20-m sprint [linear speed]; 505 with turns from each leg; modified T-test with movement to left and right [change-of-direction speed]; bilateral and unilateral vertical and standing broad jumps; lateral jumps [leg power]). Nine healthy female recreational team sport athletes (age = 22.67 ± 5.12 years; height = 1.66 ± 0.05 m; body mass = 64.22 ± 4.44 kilograms) were screened in the FMS and completed the afore-mentioned tests. Percentage between-leg differences in unilateral sit-and-reach, 505 turns and the jumps, and difference between the T-test conditions, were also calculated. Spearmans correlations (p ≤ 0.05) examined relationships between the FMS and performance tests. Stepwise multiple regressions (p ≤ 0.05) were conducted for the performance tests to determine FMS predictors. Unilateral sit-and-reach positive correlated with the left-leg ASLR (r = 0.704-0.725). However, higher-scoring HS, ILL, and ASLR related to poorer 505 and T-test performance (r = 0.722-0.829). A higher-scored left-leg ASLR related to a poorer unilateral vertical and standing broad jump, which were the only significant relationships for jump performance. Predictive data tended to confirm the correlations. The results suggest limitations in using the FMS to identify movement deficiencies that could negatively impact athletic performance in female team sport athletes.

Can Selected Functional Movement Screen Assessments Be Used to Identify Movement Deficiencies That Could Affect Multidirectional Speed and Jump Performance

Abstract Lockie, RG, Schultz, AB, Jordan, CA, Callaghan, SJ, Jeffriess, MD, and Luczo, TM. Can selected functional movement screen assessments be used to identify movement deficiencies that could affect multidirectional speed and jump performance? J Strength Cond Res 29(1): 195–205, 2015—The Functional Movement Screen (FMS) includes lower-body focused tests (deep squat [DS], hurdle step, in-line lunge) that could assist in identifying movement deficiencies affecting multidirectional sprinting and jumping, which are important qualities for team sports. However, the hypothesized relationship with athletic performance lacks supportive research. This study investigated relationships between the lower-body focused screens and overall FMS performance and multidirectional speed and jumping capabilities in team sport athletes. Twenty-two healthy men were assessed in the FMS, and multidirectional speed (0- to 5-m, 0- to 10-m, 0- to 20-m sprint intervals; 505 and between-leg turn differences, modified T-test and differences between initial movement to the left or right); and bilateral and unilateral multidirectional jumping (vertical [VJ], standing long [SLJ], and lateral jump) tests. Pearsons correlations (r) were used to calculate relationships between screening scores and performance tests (p ⩽ 0.05). After the determination of any screens relating to athletic performance, subjects were stratified into groups (3 = high-performing group; 2 = intermediate-performing group; 1 = low-performing group) to investigate movement compensations. A 1-way analysis of variance (p ⩽ 0.05) determined any between-group differences. There were few significant correlations. The DS did moderately correlate with between-leg 505 difference (r = −0.423), and bilateral VJ (r = −0.428) and SLJ (r = −0.457). When stratified into groups according to DS score, high performers had a 13% greater SLJ when compared with intermediate performers, which was the only significant result. The FMS seems to have minimal capabilities for identifying movement deficiencies that could affect multidirectional speed and jumping in male team sport athletes.

Influence of Sprint Acceleration Stance Kinetics on Velocity and Step Kinematics in Field Sport Athletes

Abstract Lockie, RG, Murphy, AJ, Schultz, AB, Jeffriess, MD, and Callaghan, SJ. Influence of sprint acceleration stance kinetics on velocity and step kinematics in field sport athletes. J Strength Cond Res 27(9): 2494–2503, 2013—The interaction between step kinematics and stance kinetics determines sprint velocity. However, the influence that stance kinetics has on effective acceleration in field sport athletes requires clarification. About 25 men (age = 22.4 ± 3.2 years; mass = 82.8 ± 7.2 kg; height = 1.81 ± 0.07 m) completed twelve 10-m sprints, 6 sprints each for kinematic and kinetic assessment. Pearsons correlations (p ⩽ 0.05) examined relationships between 0–5, 5–10, and 0–10 m velocity; step kinematics (mean step length [SL], step frequency, contact time [CT], flight time over each interval); and stance kinetics (relative vertical, horizontal, and resultant force and impulse; resultant force angle; ratio of horizontal to resultant force [RatF] for the first, second, and last contacts within the 10-m sprint). Relationships were found between 0–5, 5–10, and 0–10 m SL and 0–5 and 0–10 m velocity (r = 0.397–0.535). CT of 0–5 and 0–10 m correlated with 5–10 m velocity (r = −0.506 and −0.477, respectively). Last contact vertical force correlated with 5–10 m velocity (r = 0.405). Relationships were established between the second and last contact vertical and resultant force and CT over all intervals (r = −0.398 to 0.569). First and second contact vertical impulse correlated with 0–5 m SL (r = 0.434 and 0.442, respectively). Subjects produced resultant force angles and RatF suitable for horizontal force production. Faster acceleration in field sport athletes involved longer steps, with shorter CT. Greater vertical force production was linked with shorter CT, illustrating efficient force production. Greater SLs during acceleration were facilitated by higher vertical impulse and appropriate horizontal force. Speed training for field sport athletes should be tailored to encourage these technique adaptations.

The relationship between bilateral differences of knee flexor and extensor isokinetic strength and multi-directional speed

This study analyzed relationships between bilateral concentric (60 ◦ /s, 180 ◦ /s, 240 ◦ /s) and eccentric (30 ◦ /s) knee extensor and flexor strength differences, and linear (40-meter sprint), and change-of-direction (T-test) speed in 16 male team sport athletes. It was hypothesized that lower between-leg strength differences would be associated with faster speeds. Subjects were divided into faster and slower groups based on total time; a one-way analysis of variance (p 0.05) determined bilateral torque and work differences that distinguished the groups. All data was combined to correlate (p 0.05) torque and work differences with sprint times. The faster group exhibited greater differences in concentric knee extensor torque at 240 ◦ /s (faster = 11.74 ± 8.65%; slower = 4.13 ± 4.34%), and smaller differences in eccentric knee flexor torque (faster = 5.64 ± 4.10%; slower = 12.41 ± 7.55%) and work (faster = 6.36 ± 6.65%; slower = 15.55 ± 6.05%). Negative correlations were found between concentric 180 ◦ /s and 240 ◦ /s knee extensor torque differences and sprint times; however, speed was not negatively affected. Positive correlations existed between eccentric knee flexor work differences and sprint times. Eccentric strength differences negatively impacted multi-directional speed, as balanced eccentric strength is necessary for effective sprinting, deceleration, and changing direction.

QUANTIFYING SESSION RATINGS OF PERCEIVED EXERTION FOR FIELD-BASED SPEED TRAINING METHODS IN TEAM SPORT ATHLETES

Abstract Lockie, RG, Murphy, AJ, Scott, BR, and Janse de Jonge, XAK. Quantifying session ratings of perceived exertion for field-based speed training methods in team sport athletes. J Strength Cond Res 26(10): 2721–2728, 2012—Session ratings of perceived exertion (session RPE) are commonly used to assess global training intensity for team sports. However, there is little research quantifying the intensity of field-based training protocols for speed development. The studys aim was to determine the session RPE of popular training protocols (free sprint [FST], resisted sprint [RST], and plyometrics [PT]) designed to improve sprint acceleration over 10 m in team sport athletes. Twenty-seven men (age = 23.3 ± 4.7 years; mass = 84.5 ± 8.9 kg; height = 1.83 ± 0.07 m) were divided into 3 groups according to 10-m velocity. Training consisted of an incremental program featuring two 1-hour sessions per week for 6 weeks. Subjects recorded session RPE 30 minutes post training using the Borg category-ratio 10 scale. Repeated measures analysis of variance found significant (p < 0.05) changes in sprint velocity and session RPE over 6 weeks. All groups significantly increased 0- to 5-m velocity and 0- to 10-m velocity by 4–7%, with no differences between groups. There were no significant differences in session RPE between the groups, suggesting that protocols were matched for intensity. Session RPE significantly increased over the 6 weeks for all groups, ranging from 3.75 to 5.50. This equated to intensities of somewhat hard to hard. Post hoc testing revealed few significant weekly increases, suggesting that session RPE may not be sensitive to weekly load increases in sprint and plyometric training programs. Another explanation, however, could be that the weekly load increments used were not great enough to increase perceived exertion. Nonetheless, the progressive overload of each program was sufficient to improve 10-m sprint performance. The session RPE values from the present study could be used to assess workload for speed training periodization within a team sports conditioning program.

Effect of Different Sprint Training Methods on Sprint Performance Over Various Distances: A Brief Review.

Abstract Rumpf, MC, Lockie, RG, Cronin, JB, and Jalilvand, F. Effect of different sprint training methods on sprint performance over various distances: a brief review. J Strength Cond Res 30(6): 1767–1785, 2016—Linear sprinting speed is an essential physical quality for many athletes. There are a number of different training modalities that can be used to improve sprint performance. Strength and conditioning coaches must select the most appropriate modalities for their athletes, taking into consideration the sprint distances that typically occur during competition. The study purpose was to perform a brief review as to the effect of specific (free sprinting; resisted sprinting by sleds, bands, or incline running; assisted sprinting with a towing device or a downhill slope), nonspecific (resistance and plyometric training), and combined (a combination of specific and nonspecific) training methods on different sprint distances (0–10, 0–20, 0–30, and 31+ m). A total of 48 studies fulfilled the inclusion criteria, resulting in 1,485 subjects from a range of athletic backgrounds. The training effects associated with specific sprint training were classified as moderate (effect size [ES] = −1.00; %change = −3.23). Generally, the effect of specific sprint training tended to decrease with distance, although the largest training effects were observed for the 31+ m distance. The greatest training effects (ES = −0.43; %change = −1.65) of nonspecific training were observed for the 31+ m distance. The combined training revealed greatest effects (ES = −0.59; %change = −2.81) for the 0–10 m distance. After this review, specific sprint training methods seem the most beneficial over the investigated distances. However, the implementation of nonspecific training methods (e.g., strength and power training) could also benefit speed and athletic performance.

Contributing Factors to Change-of-Direction Ability in Professional Rugby League Players.

Abstract Delaney, JA, Scott, TJ, Ballard, DA, Duthie, GM, Hickmans, JA, Lockie, RG, and Dascombe, BJ. Contributing factors to change-of-direction ability in professional rugby league players. J Strength Cond Res 29(10): 2688–2696, 2015—Rugby league is an intermittent team sport in which players are regularly required to accelerate, decelerate, and change direction rapidly. This study aimed to determine the contributing factors to change-of-direction (COD) ability in professional rugby league players and to validate the physical and physiological components of a previously proposed COD ability predictor model. Thirty-one male professional rugby league players (age: 24.3 ± 4.4 years; height: 1.83 ± 0.06 m; body mass: 98.1 ± 9.8 kg) were assessed for anthropometry, linear speed, various leg muscle qualities, and COD ability. Change-of-direction ability was assessed for both the dominant (D) and nondominant (ND) legs using the 505 test. Stepwise multiple regression analyses determined the combined effect of the physical and physiological variables on COD ability. Maximal linear speed (SpMax) and relative squat strength (squat:BM) explained 61% of the variance in 505-D performance, whereas measures of mass, unilateral, and bilateral power contributed 67% to 505-ND performance. These results suggest that the 505-ND task was heavily dependent on relative strength and power, whereas the 505-D task was best predicted by linear sprint speed. Second, the physical component of the COD predictor model demonstrated poor correlations (r = −0.1 to −0.5) between absolute strength and power measures and COD ability. When made relative to body mass, strength and power measures and COD ability shared stronger relationships (r = −0.3 to −0.7). Change-of-direction ability in professional rugby league players would be best improved through increases in an athletes strength and power while maintaining lean muscle mass.