Farzad Jalilvand

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.

Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics

Abstract This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a fivebound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson’s correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54). The 5BT (5-10 and 0-10 m intervals) and RSI (5-10 m interval) also related to velocity (r = 0.37-0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51), and a longer 0-10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r2 = 0.14-0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.

Yo-Yo Intermittent Recovery Test Level 2 and Its Relationship With Other Typical Soccer Field Tests in Female Collegiate Soccer Players

Abstract Lockie, RG, Jalilvand, F, Moreno, MR, Orjalo, AJ, Risso, FG, and Nimphius, S. Yo-Yo intermittent recovery test level 2 and its relationship with other typical soccer field tests in female collegiate soccer players. J Strength Cond Res 31(10): 2667–2677, 2017—The ability to complete high-intensity running is essential for soccer. The Yo-Yo Intermittent Recovery Test Level 2 (YYIRT2) can measure this capacity, but there is limited information regarding this assessment in collegiate female soccer players. This study investigated the YYIRT2 as a measure of high-intensity running in this population, and its relationship to other soccer field tests. Twenty-one players from a Division I team were recruited. In addition to the YYIRT2, subjects completed linear (0–5, 0–10, and 0–30 m sprint intervals) and change-of-direction (pro-agility and 60-yard shuttle) speed tests, as well as the YYIRT Level 1 (YYIRT1), to assess relationships with YYIRT2 by correlations (p ⩽ 0.05). The correlation of YYIRT1 with the speed tests was also assessed. The YYIRT1 and YYIRT2 were standardized using z-scores for comparison with elite benchmarks to investigate relative performance on each test. The YYIRT2 and YYIRT1 distances did not significantly correlate with those of the speed tests (r = −0.251 to 0.274). There was a large relationship between YYIRT2 and YYIRT1 distances (r = 0.582), although the explained variance was low (33.87%). Mean YYIRT2 z-scores (−4.29 ± 1.66) indicated a performance further from elite benchmarks than those of the YYIRT1 (−1.92 ± 1.61), and 90.5% (19 of 21) subjects performed relatively better in the YYIRT1 than YYIRT2. The YYIRT2 provided a more specific measure of high-intensity running to that of the YYIRT1 in collegiate female soccer players. Coaches may consider using the YYIRT2 to gauge and track progress of high-intensity running capabilities and create training programs to improve this ability in female players.

Research-Grade Scoring for the Functional Movement Screen and Relationships with Athletic Performance Tests in Team Sport Athletes

Study background: There are limitations in using the traditional Functional Movement Screen (FMS) to identify deficiencies affecting athletic performance. Despite this, no research has analyzed the research-grade FMS scoring system with regards to athletic performance, where screens are weighted to increase their sensitivity. This research investigated relationships between the research-grade FMS and selected screens, with multidirectional speed and jump tests typically used to assess team sport athletes. Methods: Thirty-two male recreational team sport athletes were assessed in the FMS using research-grade scoring, and multidirectional speed (20-meter sprint; 505 change-of-direction speed test) and jump (bilateral and unilateral vertical, standing broad, and lateral) tests. Participants were dichotomized into higher-, intermediate-, and lower-performing groups according to overall research-grade FMS score to ascertain whether participants who scored better in the screens also performed better in the athletic tests. A one-way analysis of variance determined any significant (p<0.05) between-group differences for sprinting and jumping performance. Correlations (r; p<0.05), scatter plots and regression equations were calculated for selected individual research-grade scored screens (deep squat, hurdle step, and in-line lunge) and the performance tests. These screens were selected due to movement pattern similarities (i.e., lower-body triple extension) with sprinting and jumping. Results: There were no significant between-group differences in any of the multidirectional sprint or jumps tests. The deep squat positively correlated with the bilateral vertical and standing broad jump, and left-leg standing broad and lateral jump (r=0.37-0.52), although the explained variability from the regression equations were low (14-27%). The left-leg in-line lunge correlated with the bilateral and left-leg standing broad jump, and lateral jumps for both legs (r=0.38-0.50), with low explained variability (15-25%). Conclusion: Despite the increased scoring sensitivity, the research-grade FMS, and individual screens, have a similarly limited capacity to identify any movement deficiencies that relate to multidirectional sprinting and jumping in team sport athletes.

A Methodological Report: Adapting the 505 Change-of-Direction Speed Test Specific to American Football.

Abstract Lockie, RG, Jalilvand, F, Orjalo, AJ, Giuliano, DV, Moreno, MR, and Wright, GA. A methodological report: Adapting the 505 change-of-direction speed test specific to American football. J Strength Cond Res 31(2): 539–547, 2017—The 505 involves a 10-m sprint past a timing gate, followed by a 180° change-of-direction (COD) performed over 5 m. This methodological report investigated an adapted 505 (A505) designed to be football-specific by changing the distances to 10 and 5 yd. Twenty-five high school football players (6 linemen [LM]; 8 quarterbacks, running backs, and linebackers [QB/RB/LB]; 11 receivers and defensive backs [R/DB]) completed the A505 and 40-yd sprint. The difference between A505 and 0 to 10-yd time determined the COD deficit for each leg. In a follow-up session, 10 subjects completed the A505 again and 10 subjects completed the 505. Reliability was analyzed by t-tests to determine between-session differences, typical error (TE), and coefficient of variation. Test usefulness was examined via TE and smallest worthwhile change (SWC) differences. Pearsons correlations calculated relationships between the A505 and 505, and A505 and COD deficit with the 40-yd sprint. A 1-way analysis of variance (p ⩽ 0.05) derived between-position differences in the A505 and COD deficit. There were no between-session differences for the A505 (p = 0.45–0.76; intraclass correlation coefficient = 0.84–0.95; TE = 2.03–4.13%). Additionally, the A505 was capable of detecting moderate performance changes (SWC0.5 > TE). The A505 correlated with the 505 and 40-yard sprint (r = 0.58–0.92), suggesting the modified version assessed similar qualities. Receivers and defensive backs were faster than LM in the A505 for both legs, and right-leg COD deficit. Quarterbacks, running backs, and linebackers were faster than LM in the right-leg A505. The A505 is reliable, can detect moderate performance changes, and can discriminate between football position groups.

Certain Actions from the Functional Movement Screen Do Not Provide an Indication of Dynamic Stability

Abstract Dynamic stability is an essential physical component for team sport athletes. Certain Functional Movement Screen (FMS) exercises (deep squat; left- and right-leg hurdle step; left- and right-leg in-line lunge [ILL]; left- and right-leg active straight-leg raise; and trunk stability push-up [TSPU]) have been suggested as providing an indication of dynamic stability. No research has investigated relationships between these screens and an established test of dynamic stability such as the modified Star Excursion Balance Test (mSEBT), which measures lower-limb reach distance in posteromedial, medial, and anteromedial directions, in team sport athletes. Forty-one male and female team sport athletes completed the screens and the mSEBT. Participants were split into high-, intermediate-, and low-performing groups according to the mean of the excursions when both the left and right legs were used for the mSEBT stance. Any between-group differences in the screens and mSEBT were determined via a one-way analysis of variance with Bonferroni post hoc adjustment (p < 0.05). Data was pooled for a correlation analysis (p < 0.05). There were no between-group differences in any of the screens, and only two positive correlations between the screens and the mSEBT (TSPU and right stance leg posteromedial excursion, r = 0.37; left-leg ILL and left stance leg posteromedial excursion, r = 0.46). The mSEBT clearly indicated participants with different dynamic stability capabilities. In contrast to the mSEBT, the selected FMS exercises investigated in this study have a limited capacity to identify dynamic stability in team sport athletes.

An introductory analysis as to the influence of lower-body power on multidirectional speed in collegiate female rugby players

Abstract This study investigated relationships between lower-body power, measured by a vertical jump (VJ) and standing broad jump (SBJ), with multidirectional speed in collegiate female rugby players. The rugby player data was compared to that of general team sport athletes to ascertain whether there were characteristics specific to collegiate rugby players. Multi-directional speed was measured by a 20-meter (m) sprint (0-5, 0-10, 0-20 m intervals) and 505 change-of-direction speed test. Eight rugby players and eight team sport athletes completed all tests. Spearman’s correlations calculated relationships between the VJ and SBJ with the speed tests, and stepwise multiple regressions determined whether the jump tests predicted speed performance (p ≤ 0.05). For the rugby players, the VJ correlated with the 0-20 m interval (r = −0.73). The SBJ correlated with the 0-5 and 0-10 m intervals, and the left-leg 505 (r = −0.71 to −0.88), and predicted 0-5 m and left-leg 505 time (r2 = 0.50-0.58). For the team sport athletes, only the VJ correlated with left-leg 505 (r = −0.80), and predicted left- and right-leg 505 times (r2 = 0.61-0.69). The results suggest that horizontal power measured by a SBJ has a greater contribution to multidirectional speed in collegiate female rugby players.

The Relationship between Unilateral Dynamic Stability and Multidirectional Jump Performance in Team Sport Athletes

Abstract This study investigated relationships between dynamic stability and multidirectional jumping. A modified Star Excursion Balance Test (mSEBT), incorporating unilateral lower-body reaching in posteromedial, medial, and anteromedial directions, assessed dynamic stability. Unilateral vertical (VJ), standing broad (SBJ) and lateral jumps (LJ) assessed leg power. VJ power and relative SBJ and LJ distances were calculated. Thirty-two team sport athletes completed the mSEBT when each leg was used for stance, and left- and right-leg VJ, SBJ, and LJ. Correlations were drawn between data recorded from each leg when used for mSEBT stance and for each jump. Participants were dichotomized into better and lesser dynamic stability groups according to the sum of excursions for each leg. A one-way ANOVA determined mSEBT and jump differences (p < 0.05). The left-leg posteromedial and medial excursions correlated with VJ power; the medial excursion correlated with the LJ. The right-leg posteromedial excursion correlated with the SBJ; the anteromedial excursion correlated with the SBJ, and relative SBJ and LJ (r = 0.35-0.45). There were no differences in unilateral jumping between the better and lesser groups. Although there is some relationship with dynamic stability, this study further highlighted the complex interaction between the physical and technical characteristics of multidirectional jumping.