Abstract
d to compare two female field hockey teams of different competitive levels by analyzing kinematic variables in repeated sprint ability (RSA) tests and the force-velocity profile (FVP). Twenty-five female hockey players representing the elite and subelite levels from the same club volunteered to participate. The RSA protocol included six 30 m maximal sprints with a 30 s recovery. Kinematic variables, such as sprint time, step frequency, and step length, were analyzed for each sprint. Additionally, players performed counter-movement jumps (CMJs) and CMJs with 50% body weight (CMJ50s) to calculate the FV50 using the Bosco Index. The elite players showed better (≈2%;p< 0.05) fatigue
participate. The RSA protocol included six 30 m maximal sprints with a 30 s recovery. Kinematic variables, such as sprint time, step frequency, and step length, were analyzed for each sprint. Additionally, players performed counter-movement jumps (CMJs) and CMJs with 50% body weight (CMJ50s) to calculate the FV50 using the Bosco Index. The elite players showed better (≈2%;p< 0.05) fatigue indexes in sprint time (0–30 m and 0–10 m sections), step length (0–10 m, 10–20 m, and 20–30 m sections), and step frequency (20–30 m section) during the RSA test, as well as greater values (>10%;p< 0.05) in the CMJ50 and FV50 tests. In addition, these RSA (sprint time, step frequency, and step length) and jumping (CMJ, CMJ50, and FV50) variables showed a moderate, significant, or very significant relationship with each other. Therefore, it seems that both strength and speed capacities can be used either in conjunction or as a complementary approach to enhance the overall RSA performance. Keywords:sport performance; monitoring and evaluation; team sports; fatigue index; sprint time; Bosco Index 1. Introduction Field hockey is a team sport characterized by the execution of high-intensity actions, like sprints, jumps, changes in direction, and shoots [1], which have a great influence on the match outcome [2]. For this reason, it is very important to enhance the ability to repeat high-intensity activities [3] and to avoid an impairment of performance in the course of a match due to the gradual development of fatigue [4]. Repeated sprint ability (RSA) tests have been frequently employed in team sports to assess the ability to repeat high-intensity actions in team sports [3]. These tests are composed of a series of repeated sprints, characterized by short efforts (e.g., 30–40 m sprints) and an incomplete recovery between them [3]. The mean time of the sprints, the overall sum of the time employed in all the repetitions, or the fatigue indexes comparing Appl. Sci.2024,14, 9003.
Appl. Sci.2024,14, 9003 2 of 10 the fastest, mean, and slowest repetitions are used to assess the performance in the test. This can be complemented with the evaluation of running cyclic parameters such as the step frequency (SF) and the step length (SL), which provide further information on how fatigue can affect the running performance [5–8]. Fatigue indexes between 3% and 6% have been identified as reference values in different sports and performance levels [5,9–12]. In addition, the force–velocity profile (FVP) using counter-movement jumps (CMJs) has been identified as an indicator of neuromuscular capacities in both sprint [13] and RSA performance [14]. Recently, the calculation of the FVP with the use of two loads (20–70%, 1 repetitionmaximum; RM) has been proposed as a reliable procedure [15]. Specifically, the FVP50 (or Bosco test, 0–50% body weight loads) has shown a relationship with physical performance, both in individual [16] and team sports [5], thus facilitating easier assessment without requiring a 1 RM test. In addition to the relationships shown between jumping and sprint, plyometric training (based on CMJs and ankle jumps) has been found beneficial for improving RSA performance in athletes [17]. The differences in the metabolic and neuromuscular components of team sport players from diverse competitive standards have recently been addressed in the literature [18]. Soc- cer [19] and handball players [20] have shown greater performances in repeated sprinting and vertical jumping, whereas no statistical differences were observed in futsal players [21]. However, these studies have not complemented the analysis of RSA with running kinemat- ics, nor used vertical jumps with external loads to calculate the FVP. Therefore, the aim of this study was to analyze the kinematic differences between the RSA test and the FVP50 in two, elite vs. subelite, female field hockey athletes. Additionally, correlations between the analyzed kinematic variables (e.g., step length and step frequency) were also explored. 2. Materials and Methods 2.1. Participants Twenty-five female field hockey players (age 24.92±5.56 years; body height1.67±0.04 m ; body weight 58.72±3.71 kg) volunteered to take part in this study. Participants were both elite (n= 13; age 26.31±4,97 years; body height
female field hockey athletes. Additionally, correlations between the analyzed kinematic variables (e.g., step length and step frequency) were also explored. 2. Materials and Methods 2.1. Participants Twenty-five female field hockey players (age 24.92±5.56 years; body height1.67±0.04 m ; body weight 58.72±3.71 kg) volunteered to take part in this study. Participants were both elite (n= 13; age 26.31±4,97 years; body height 1.66±0.04 m; body weight59.00±3.03 kg ) and subelite (n= 12; age 23.42±5.98 years; body height 1.67±0.04 m; body weight 58.42±4.46 kg ) players from the first (national champion and European championship runner-up) and second (national second division) teams of the same club, respectively. This study received approval from the Local University Ethics Committee (CODE 35/2020), and all the participants provided their informed consent, in accordance with the principles of the Declaration of Helsinki. Additionally, all the participants were thoroughly briefed on the study’s protocol. 2.2. Design To ensure minimal disruption to their regular training routines, all coaching and support staff were informed and, in some cases, actively involved in the design of the study and its supervision. All the tests were conducted during the conditioning segment of the workouts at the beginning of the training session and after the completion of a standardized warm-up (Figure). The jumping tests were administered on Tuesday (regular resistance training session), while the repeated sprint ability (RSA) test was performed on Thursday (regular speed training workout), at the same time of day (8:00 p.m.) during a regular competition week in which they played against a lower-level team.
Appl. Sci.2024,14, 9003 3 of 10Appl. Sci. 2024, 14, x FOR PEER REVIEW 3 of 11 Figure 1. Jumping and RSA test protocols. 2.3. Repeated Sprint Ability Test The repeated sprint ability (RSA) protocol involved six 30 m maximal sprints, with a 30 s active recovery period after each sprint being implemented [10]. Before the test, the players carried out a standardized and specific 15 min warm-up composed of 5 min of jogging and general movements, 2 min of dynamic stretching, 3 min of running drills, and 5 min of 5 to 10 m accelerations. During the recovery time, the participants decelerated for a maximum of 10 m and followed a triangle form circuit to return to the starting line [10]. Thereafter, they repeated the sprint for a total of six repetitions. Electronic photocells (Mi- crogate, Bolzano, Italy) were used to measure sprinting times. The photocells were posi- tioned at 0, 10, 20, and 30 m, with their heights adjusted in accordance with the partici- pants’ height. The starting position of the players was fixed, standing still 1 m behind the initial timing gates. An EX-ZR800 video-camera (Casio Computer Co., Tokyo, Japan) op- erating at 60 Hz with specific settings (shutter speed: 1/1000, resolution: 1920 × 1080 pixels) was used to record the 30 m sprints. 2.4. Estimation of the Step Frequency (SF) and Length (SL) The SF was calculated by dividing the number of steps by the time it took to perform the sprint and the SL by dividing the sprint distance by the sprint time and SF in each section (0–10 m, 10–20 m, 20–30 m and 0–30 m) for the six sprints. In addition, to estimate the performance decrease, the following fatigue indexes were calculated: FImean = 100 − (mean/best × 100)) and worst (FIworst = 100 – (worst/best × 100)) repetition during the test [5]. 2.5. Jump Test All the players carried out CMJ and CMJ50 tests preceded by a 10 min warm-up com- posed of 2 min of general activation, 2 min of light active stretching focused primarily on the lower limbs, 3 min of
100 − (mean/best × 100)) and worst (FIworst = 100 – (worst/best × 100)) repetition during the test [5]. 2.5. Jump Test All the players carried out CMJ and CMJ50 tests preceded by a 10 min warm-up com- posed of 2 min of general activation, 2 min of light active stretching focused primarily on the lower limbs, 3 min of basic bodyweight muscular activation (10 repetitions of lunges, squats, hip-thrusts, and single-leg Romanian deadlifts), and 3 min of explosive activation (involving six repetitions of squat jumps, CMJs, and Drop Jumps, with complete rest in- tervals between them). All jumping tests were carried out on a contact platform (Chronojump—Bosco Sys- tem, Barcelona, Spain), which allowed us to measure flight times, and the calculation of the jumping height was carried out using the Chronojump Sofware (Bosco System v 2.35, Barcelona, Spain). Each player performed three jumps for each test, and only the best score was considered for the analysis. From a standing position, all the participants performed a fast knee flexion to thereafter jump as high as possible while maintaining a vertical body Figure 1.Jumping and RSA test protocols. 2.3. Repeated Sprint Ability Test The repeated sprint ability (RSA) protocol involved six 30 m maximal sprints, with a 30 s active recovery period after each sprint being implemented [10]. Before the test, the players carried out a standardized and specific 15 min warm-up composed of 5 min of jogging and general movements, 2 min of dynamic stretching, 3 min of running drills, and 5 min of 5 to 10 m accelerations. During the recovery time, the participants decelerated for a maximum of 10 m and followed a triangle form circuit to return to the starting line [10]. Thereafter, they repeated the sprint for a total of six repetitions. Electronic photocells (Microgate, Bolzano, Italy) were used to measure sprinting times. The photocells were positioned at 0, 10, 20, and 30 m, with their heights adjusted in accordance with the participants’ height. The starting position of the players was fixed, standing still 1 m behind the initial timing gates. An EX-ZR800 video-camera (Casio Computer
for a total of six repetitions. Electronic photocells (Microgate, Bolzano, Italy) were used to measure sprinting times. The photocells were positioned at 0, 10, 20, and 30 m, with their heights adjusted in accordance with the participants’ height. The starting position of the players was fixed, standing still 1 m behind the initial timing gates. An EX-ZR800 video-camera (Casio Computer Co., Tokyo, Japan) operating at 60 Hz with specific settings (shutter speed: 1/1000, resolution: 1920×1080 pixels) was used to record the 30 m sprints. 2.4. Estimation of the Step Frequency (SF) and Length (SL) The SF was calculated by dividing the number of steps by the time it took to perform the sprint and the SL by dividing the sprint distance by the sprint time and SF in each sec- tion (0–10 m, 10–20 m, 20–30 m and 0–30 m) for the six sprints. In addition, to estimate the performance decrease, the following fatigue indexes were calculated: FImean = 100− (mean/best×100 )) and worst (FIworst = 100 – (worst/best×100 )) repetition during the test [5]. 2.5. Jump Test All the players carried out CMJ and CMJ50 tests preceded by a 10 min warm-up composed of 2 min of general activation, 2 min of light active stretching focused primarily on the lower limbs, 3 min of basic bodyweight muscular activation (10 repetitions of lunges, squats, hip-thrusts, and single-leg Romanian deadlifts), and 3 min of explosive activation (involving six repetitions of squat jumps, CMJs, and Drop Jumps, with complete rest intervals between them). All jumping tests were carried out on a contact platform (Chronojump—Bosco System, Barcelona, Spain), which allowed us to measure flight times, and the calculation of the jumping height was carried out using the Chronojump Sofware (Bosco System v 2.35, Barcelona, Spain). Each player performed three jumps for each test, and only the best score was considered for the analysis. From a standing position, all the participants performed a fast knee flexion to thereafter jump as high as possible while maintaining a vertical body position at take-off and landing with their knees fully extended and avoiding any lateral or frontal
Barcelona, Spain). Each player performed three jumps for each test, and only the best score was considered for the analysis. From a standing position, all the participants performed a fast knee flexion to thereafter jump as high as possible while maintaining a vertical body position at take-off and landing with their knees fully extended and avoiding any lateral or frontal movements [22]. During the CMJ50 test, an additional load (bar) equivalent to 50%
Appl. Sci.2024,14, 9003 4 of 10 of the body weight of each participant was used. To ensure consistency between the CMJs and CMJ50s, the players held a plastic barbell (with no overload) in the CMJs to mimic the execution of the CMJ50s. The FV50 proposed by Bosco was determined using the following equation: FV50 = CMJ50/CMJ×100 [16]. 2.6. Statistical Analysis A descriptive analysis was performed, and subsequently, the Shapiro–Wilk test was applied to assess normality. A repeated measures analysis of variance (ANOVA) was employed to compare the variables (sprint time, step frequency, and step length) within the different sections (0–10 m, 10–20 m, and 20–30 m) of the six sprints. Post hoc tests were conducted using Bonferroni corrections, and effect sizes (np2) were employed to estimate the magnitude of difference, with 0.2, 0.5, and 0.8 indicating small, moderate, or large effect sizes, respectively [23]. Furthermore, to explore the relationship between the FV50 and the RSA kinematic parameters, Pearson correlation coefficients were utilized, with 0.1, 0.3, 0.5, 0.7, and 0.9 being used as thresholds for small, moderate, large, very large, or nearly perfect correlations [24]. Results are reported as mean±standard deviation unless otherwise stated. All statistics were performed using the IBM Statistical Package for the Social Sciences (SPSS for Windows, version 27.0 (IBM Inc., Armonk, NY, USA) with alpha level set atp< 0.05. 3. Results 3.1. RSA Performance Significant main time effects were observed for the kinematic variables measured during the 30 m RSA (Figure): sprint times (F3.65 = 11.55, p< 0.001,η2 = 0.33); SF (F4.60 = 14.05,p< 0.001,η2 = 0.38); and SL (F4.43 = 2.84,p= 0.024,η2 = 0.11).Appl. Sci. 2024, 14, x FOR PEER REVIEW 5 of 11 Figure 2. Evolution of step kinematics during the six repetitions in (a) 0–30 m, (b) 0–10 m, (c) 10–20 m, and (d) 20–30 m sections for all the players during the RSA test. (*) Different from the first repe- tition at p < 0.05. 3.2. Jumping Performance The mean values of CMJ (31.06 ± 0.65 cm) and CMJ50 (17.55 ± 0.48 cm) showed dif- ferences (p < 0.001) from each other. 3.3.
0–30 m, (b) 0–10 m, (c) 10–20 m, and (d) 20–30 m sections for all the players during the RSA test. (*) Different from the first repe- tition at p < 0.05. 3.2. Jumping Performance The mean values of CMJ (31.06 ± 0.65 cm) and CMJ50 (17.55 ± 0.48 cm) showed dif- ferences (p < 0.001) from each other. 3.3. Performance Level Players from the subelite team (Table 1) exhibited higher (p < 0.05–0.01) fatigue in- dexes than those from the elite team in several cyclic running variables (sprint time, SF, and SL) throughout all the RSA sections (0–30 m, 0–10 m, 10–20 m, and 20–30 m). In addi- tion, differences were found between both teams in the worst step frequency of the 20–30 m section (p < 0.05). However, no differences were observed for the best or average values of the RSA variables and sections. Table 1. Comparison between an elite and subelite team in sprint time, step length, and step fre- quency for different parameters (best, mean, worst, and fatigue index mean and worst) during the RSA test sections (0–30 m, 0–10 m, 10–20 m, and 20–30 m). (*) Different between teams at p <0.05. Team Best Mean Worst FImean FIworst 0–30 m Sprint Time (s) Elite 4.58 ± 0.22 4.67 ± 0.23 4.73 ± 0.25 1.87 ± 1.31 3.27 ± 1.97 Subelite 4.64 ± 0.13 4.74 ± 0.16 4.87 ± 0.19 2.16 ± 0.95 4.92 ± 2.06 * Elite 4.13 ± 0.23 4.02 ± 0.25 3.93 ± 0.26 −2.78 ± 1.45 −4.95 ± 1.96 Figure 2.Evolution of step kinematics during the six repetitions in (a) 0–30 m, (b) 0–10 m, (c) 10–20 m, and (d) 20–30 m sections for all the players during the RSA test. (*) Different from the first repetition atp< 0.05.
Appl. Sci.2024,14, 9003 5 of 10 When studying the 10 m intervals of the test (Figureb–d), a small effect of the repetitions was detected for the sprint times in the 20–30 m section (F4.44 = 12.49,p< 0.001, η2 = 0.35) and for the SF of the first (F5.00 = 12.85,p< 0.001,η2 = 0.36) and last (F4.53 = 5.70, p< 0.001,η2 = 0.20) 10 m sections. Trivial effects for SL were observed in all the sections (0–10 m: F4.38 = 2.84,p= 0.024,η2 = 0.11, 10–20 m: F3.44 = 0.96,p= 0.43,η2 = 0.04 and 20–30 m: F4.61 = 2.58,p= 0.034,η2 = 0.10). Pairwise comparisons (Figure) revealed statistical differences in sprint times (p= 0.42–0.005) and SF (p= 0.005–0.001) between the first repetition and the third, fourth, fifth, and sixth repetitions during the 30 m sprint times. In the case of the SL, there were only differences (p= 0.007) between the first and fifth repetition of the 30 m sprint. When comparing the first and the last repetition of the 30 m test, the sprint time increased by 2.1% (p= 0.017), the SF decreased by 2.4% (p= 0.004), whereas there were no differences (p> 0.05) in the SL. 3.2. Jumping Performance The mean values of CMJ (31.06±0.65 cm) and CMJ50 (17.55±0.48 cm) showed differences (p< 0.001) from each other. 3.3. Performance Level Players from the subelite team (Table) exhibited higher ( p< 0.05–0.01) fatigue indexes than those from the elite team in several cyclic running variables (sprint time, SF, and SL) throughout all the RSA sections (0–30 m, 0–10 m, 10–20 m, and 20–30 m). In addition, differences were found between both teams in the worst step frequency of the 20–30 m section (p< 0.05). However, no differences were observed for the best or average values of the RSA variables and sections. Table 1.Comparison between an elite and subelite team in sprint time, step length, and step frequency for different parameters (best, mean, worst, and fatigue index mean and worst) during the RSA test sections (0–30 m, 0–10 m, 10–20 m, and 20–30 m). (*) Different between teams atp< 0.05. Team Best Mean Worst
average values of the RSA variables and sections. Table 1.Comparison between an elite and subelite team in sprint time, step length, and step frequency for different parameters (best, mean, worst, and fatigue index mean and worst) during the RSA test sections (0–30 m, 0–10 m, 10–20 m, and 20–30 m). (*) Different between teams atp< 0.05. Team Best Mean Worst FImean FIworst 0–30 m Sprint Time (s) Elite 4.58 ±0.22 4.67 ±0.23 4.73 ±0.25 1.87 ±1.31 3.27 ±1.97 Subelite 4.64 ±0.13 4.74 ±0.16 4.87 ±0.19 2.16 ±0.95 4.92 ±2.06 * Step Frequency (Hz) Elite 4.13 ±0.23 4.02 ±0.25 3.93 ±0.26 −2.78±1.45 −4.95±1.96 Subelite 4.07 ±0.17 3.97 ±0.16 3.87 ±0.16 −2.31±1.02 −4.68±1.97 Step Length (m) Elite 1.63 ±0.11 1.61 ±0.11 1.58 ±0.10 −1.64±0.74 −3.45±0.97 Subelite 1.63 ±0.07 1.60 ±0.07 1.56 ±0.06 −2.07±1.00 −4.45±2.21 0–10 m Sprint Time (s) Elite 1.85 ±0.09 1.89 ±0.09 1.92 ±0.08 2.28 ±1.44 4.13 ±2.05 Subelite 1.84 ±0.07 1.90 ±0.07 1.96 ±0.09 3.39 ±1.67 6.79 ±2.20 * Step Frequency (Hz) Elite 4.13 ±0.23 4.02 ±0.25 3.93 ±0.26 −2.78±1.45 −4.95±1.96 Subelite 4.05 ±0.17 3.95 ±0.16 3.86 ±0.16 −2.50±0.84 −4.78±1.04 Step Length (m) Elite 1.36 ±0.10 1.33 ±0.09 1.30 ±0.09 −2.13±0.78 −4.37±1.45 Subelite 1.39 ±0.07 1.34 ±0.07 1.29 ±0.08 −4.11±2.24 * −7.18±2.95 * 10–20 m Sprint Time (s) Elite 1.38 ±0.07 1.41 ±0.07 1.44 ±0.08 2.02 ±1.41 3.82 ±2.13 Subelite 1.41 ±0.04 1.44 ±0.04 1.47 ±0.05 1.84 ±0.94 3.88 ±1.58 Step Frequency (Hz) Elite 4.26 ±0.27 4.17 ±0.27 4.07 ±0.29 −2.32±1.37 −4.54±1.99 Subelite 4.25 ±0.27 4.11 ±0.17 4.01 ±0.17 −3.02±3.51 −5.52±4.48 Step Length (m) Elite 1.74 ±0.11 1.71 ±0.11 1.67 ±0.12 −1.95±0.65 −4.00±1.45 Subelite 1.74 ±0.06 1.69 ±0.06 1.64 ±0.08 −2.79±0.87 * −6.14±3.84 20–30 m Sprint Time (s) Elite 1.34 ±0.08 1.37 ±0.08 1.40 ±0.09 2.55 ±1.08 4.91 ±1.78 Subelite 1.36 ±0.05 1.40 ±0.06 1.45 ±0.06 3.05 ±1.48 6.74 ±3.60 Step Frequency (Hz) Elite 4.11 ±0.30 4.01 ±0.29 3.90 ±0.30 −2.48±1.12 −5.15±2.41 Subelite 4.03 ±0.20 3.85 ±0.21 3.67 ±0.24 * −4.43±1.87 * −9.10±4.21 * Step Length (m) Elite 1.88 ±0.13 1.83 ±0.12 1.79 ±0.12 −2.54±0.65 −4.92±1.16 Subelite 1.94 ±0.13 1.86 ±0.10 1.79 ±0.08 −4.01±1.91 * −7.76±3.57 *
Description
The study compares RSA and FVP in elite and subelite female field hockey players.