Sports Biomechanics Applied to Performance Optimization

Background: The study aimed to analyze the relationship between the mechanical parameters of the horizontal force–velocity profile (Hzt FV profile) and performance over two different change of direction (COD) protocols (505test and modified 505test [M505test]) to assess the influence of mechanical parameters of Hzt FV profile on COD deficit (CODD) in soccer players among different categories. Methods: Seventy-seven soccer players, divided into playing levels, participated in the following assessments: Hzt FV profile, 505test and M505test. Spearman correlation coefficient (r_s [p < 0.05]) and a linear regression model were used to determine the relationship between COD performance and mechanical parameters of sprint (maximum power output [P_max], maximum horizontal force production [F₀] and maximum velocity application [V₀]). Results: Results suggest that: (1) V0 is highly correlated with 505test [Professional (r_s = −0.682, p < 0.01); Amateurs (r_s = −0.721, p < 0.01); U18DH (r_s = −0.736, p < 0.01); U18LN (r_s = −0.569, p < 0.01)]; (2) F₀ is strongly correlated to M505test F₀—M505test [Professional (r_s = −0.468, p < 0.05); Amateurs (r_s = −0.690, p < 0.01); U18DH (r_s = −0.642, p < 0.01); U18LN (r_s = −0.658, p < 0.01)]; and (3) significant differences were observed in Professionals vs. U18LN comparison [505test (U = −37.7, p = 0.000); M505test (U = −26.9, p = 0.000)]. Conclusions: A significant relationship exists between strength levels and COD performance depending on task demands. Horizontal force (F₀) is crucial in statics COD, while high-speed force production (V₀) is decisive in dynamics COD. Finally, higher-level players demonstrate greater efficiency in COD. Full article

The running biomechanics of running shoes have been extensively investigated. However, there is limited knowledge about the use of bionic shoes compared to neutral shoes, along with the velocities involved in their use. The aim of this study was to examine the biomechanical alterations associated with various running velocities of bionic shoes. By removing different thicknesses of the forefoot section, bionic shoes created a more natural shape—close to that of a human foot. The study included 16 heel strike runners running at 10 km/h, 12 km/h and 14 km/h in bionic shoes and neutral shoes, respectively. A two-way ANOVA and SPM1d were employed for examining kinematic and kinetic differences. Regarding the results for the shoes, increased ROM was observed for the bionic shoes for the hip (p < 0.001) and ankle joints (p < 0.001). Ankle positive work (p < 0.001) and negative work (p = 0.042) also showed significant differences. Regarding the velocity results, hip ROM (p < 0.001) increased and peak knee angular velocity (p = 0.018) increased, while knee ROM (p = 0.023) decreased. The interaction effects only existed in hip (p = 0.031) and ankle (p = 0.008) ROM. The results of this study suggested that the impact of running propulsion in the bionic shoes was minimal. However, with increased velocities, the bionic shoes demonstrated the ability to absorb more force, created a more stable training environment, and contributed to injury prevention for the hip and ankle joints. Full article

Exploring resistance training methods is crucial for optimizing performance programs. Isometric muscle actions have gained popularity in athletic training, but their impact on dynamic performance is uncertain. Isolated isometric actions also lack ecological validity. We compared the effects of 8-week combined isometric and plyometric (COMB) training and contrast strength training (CST) programs on junior male handball players. Thirty-six male first national division players (17.6 ± 1.0 years) were enrolled and randomly assigned to COMB, CST, or control (CONT) groups (all n = 12). Sprinting, change of direction, ball throwing velocity, jumping, and strength were assessed pre- and post-intervention. A significant group × time interaction was observed between the COMB and CONT groups for 20 and 30 m sprints (p ≤ 0.002) and between the COMB and CST groups (p ≤ 0.042). The COMB group had the largest improvements in change of direction and the modified T-test, with significant group × time interactions between the COMB and CONT groups (p ≤ 0.021). Significant group × time interactions were observed between the COMB and CST groups and between the COMB and CONT groups for 3 step running throw (p = 0.003; p < 0.001), running throw (p = 0.02; p = 0.031), and jumping throw (p = 0.001; p < 0.001). Countermovement jump showed a significant group × time interaction (p = 0.014), with the COMB group outperforming the other groups. Generally, COMB yielded larger improvements than CST. Coaches should consider incorporating a combination of isometric and plyometric exercises for in-season strength training. Full article

Three-point shooting plays an important role in determining the outcomes of basketball games and could be relevant for player selection. However, there has been little research into the relationship between basketball players’ physical capacities, metabolic capacities, and three-point shooting accuracy, particularly among female players. The aim of this study was to examine the relationship between physical capacities, metabolic capacities, and dynamic three-point shooting accuracy in female professional basketball players. Twelve female professional basketball players from the Women’s Chinese Basketball Association (WCBA) league (age: 19.04 ± 1.31 years, height: 181.33 ± 4.90 cm, playing experience: 7.83 ± 1.7 years) were recruited for this study. Pearson correlations and multiple linear regression analysis were run to assess the relationship between physical capacities, metabolic capacities, and dynamic three-point shooting. Results showed that coordination, balance, core strength, and relative average power were positively correlated with three-point shooting accuracy (r > 0.58, p < 0.05), while no other variables showed significant correlations. The current study suggests that coaching staff should consider coordination, balance, core strength, and anaerobic capacities when selecting players as well as in their training periodization if three-point shooting accuracy is considered relevant. Full article

The sport of axe throwing has gained popularity. Axe throwing is defined as a striking sport in which competitors are required to throw an axe with accuracy and appropriate velocity. However, evidence on the role of the trunk center of mass (CoM) in axe throwing, based on in-the-field experimental settings, is lacking. The aim of this study was to understand the variation in the magnitude of trunk CoM acceleration between male and female axe throwers and its relationship to throwing accuracy. The sample consisted of 10 adult axe throwers (five males: 35.9 ± 7.5 years; five females: 25.2 ± 3.2 years) of varying skill level and experience. The axe throwers completed five single-handed overarm axe throws using their right hand. The accuracy of the axe throws was recorded, along with CoM acceleration. The overall magnitudes of trunk CoM acceleration were significantly different between the male and female axe throwers (male CoM acceleration vector: 3.6 ± 1.1; female CoM acceleration vector: 2.2 ± 0.4; p = 0.001), with males recording a higher level of accuracy (males: 76%; females: 36%) in the axe throwing task combined with greater magnitudes of vertical acceleration. Female kinematics of the trunk were observed to have significantly higher magnitudes of mediolateral acceleration (3.55 ± 1.78, p = 0.016). The overall results identified that the vector magnitude of trunk CoM acceleration was significantly correlated (r = 0.87) to performance accuracy in the male throwers. It is suggested that axe throwers should consider using trunk CoM acceleration as a viable performance metric. Full article

The upper limb force–velocity relationship (FVR) is a crucial aspect of athletic performance, particularly in para-sports where upper limb movements play a leading role in activities such as wheelchair propulsion. Athletes’ mechanical capacities can be evaluated on the field or in lab conditions. However, no studies have yet indicated a relationship between ergometers and field FVR or performances. Understanding para-athletes’ upper limb FVR can provide important insights for developing effective training programs and improving athletic performance in wheelchair basketball players. Twenty-three wheelchair basketball players (12 women and 11 men) from French national teams performed a battery of three tests consisting of a 20 m sprint (SP) with Inertial measurement units (IMU) on wheels, horizontal upper limb push-offs on a frictionless sled with two Kistler force plates (HBP), and a crank ergometer sprint test (CES) derived from arm ergometer sprints using Brachumera, Lode. For the SP test, the FVR was computed with an estimation of force from the acceleration, the rolling resistance, and an estimation of the air resistance. Correlations between each variable measured were computed via Pearson correlations in R, assuming a strong relationship when r = 0.7–1.0, moderate when r = 0.40–0.69, and weak when r < 0.1–0.39. Significant differences were assumed when p < 0.05. Strong correlations were found between the results of the three tests conducted. The correlation coefficient between maximal theoretical force (F0) data ranged from 0.85 to 0.88, and that between maximal theoretical power (P0) data ranged from 0.87 to 0.94. However, for maximal theoretical velocity (V0) data, the correlations between the three tests were less important. The performance variables showed a strong correlation with power measured in the HBP test without load. There was a significant relationship between the HBP, CES, and SP variables. There was a correlation between performance on the three tests in our population, especially for power. However, the V0 value of HBP was not representative of any performances. This work uses multiple protocols to assess para-athletes’ performance and shows that upper limb symmetry depends on the gesture of the task and the personal sports’ wheelchair. Full article

A countermovement jump (CMJ) performed on a force plate is commonly applied in soccer to quantify acute neuromuscular fatigue (NMF), which may manifest immediately following soccer match play. Jump height (JH) is the main outcome variable reported for this purpose; however, it is sensitive to alterations in movement strategy, which may act to mask JH and, therefore, mask any presence of NMF. Acute reductions in body mass (BM) during match play could also lead to the maintenance of JH, but this is yet to be explored. This study sought to explore soccer-match-induced alterations to JH, movement strategy, and BM to inform future variable selection for the study of acute NMF. Fourteen male English National League soccer players performed three CMJs on a dual-force plate system immediately before and after a competitive soccer match. Differences in jump height were non-significant and trivial (p = 0.924, g = 0.03) before and after soccer match play, but there was a large post-match decrease in BM (g = 1.66). Furthermore, moderate decreases in jump momentum (g = 0.56) and countermovement depth (g = 0.72) were noted. As JH was determined by the take-off velocity, reduced BM could have augmented it (less mass to accelerate); however, reduced countermovement depth seemingly counteracted this (less distance to attain velocity). It may, therefore, be beneficial to report these variables when monitoring acute NMF via the CMJ. Full article

Objective: The aims that we set in this study were to analyse the kinematic and kinetic changes in the lower limbs of cyclists when using the utility model, nº of publication ES 1078023, which consists of a system of cleats with an exact omnidirectional adjustment and without oscillations between the shoe and the pedal. Methods: This is a quasi-experimental, longitudinal and prospective study with a non-randomized sampling. The sample was made up of 34 cyclists. The variables studies focused on the kinematics of each joint of the lower limb in three planes and the kinetics in the function of the angular position of the cleat. They had the Bioval^® system put in place, through which the kinematic parameters were recorded at the points marked on the lower limb for 20 s. Three systems were used for the kinetics (Power Tap, Rotor and Pioneer), recording the power developed for 1 min for each of the study situations. Results: Regarding the kinematic variables, statistically significant differences were found for the three planes in all of the structures studied. As for the kinetics, statistically significant differences were also observed, both when analyzing them globally and when doing so for each of the systems. Conclusions: The variation in the rotational position of the cleat influences both the cyclist’s kinematics and dynamics. Full article

Background: A method to assess the influence of sex and side testing on trunk rotator muscles has not been described. The purpose was to analyze the influence of sex and dominant and non-dominant sides (DS-NDS) on the reliability of two trunk rotator exercises and to study the relationship between the DS-NDS of two trunk rotator strength exercises. Methods: The reliability of the horizontal cable woodchop (HCW) and low cable woodchop (LWC) exercises was studied using a test-retest design with 51 physically active students. Isokinetic and isometric strength were assessed with a functional electromechanical dynamometer. Results: There were significant differences in reliability between male and female HCW and no significant differences in reliability between the average of the DS-NDS in HCW and LCW. There were no significant differences between the DS-NDS in the sex of HCW, and the strength of the two exercises showed no significant differences except for two conditions assessed. Very large to extremely large correlations were observed between sides in the strength of two exercises (r = 0.71–0.91). Conclusions: This test is handy for physical trainers or coaches to know the strength of the trunk rotators of their athletes. Full article

This study aimed to compare and associate the magnitude of the load–velocity relationship variables between the multiple-point and two-point methods and between the concentric-only and eccentric–concentric prone bench pull (PBP) variants. Twenty-three resistance-trained males completed a preliminary session to determine the concentric-only PBP one-repetition maximum (1 RM) and two experimental sessions that only differed in the PBP variant evaluated. In each experimental session they performed three repetitions against the 14 kg load (L1), two repetitions against the 85% 1 RM load (L4), three repetitions against an equidistant intermediate light load (L2), two repetitions against an equidistant intermediate heavy load (L3), and 1–5 1 RM attempts. The load–velocity relationship variables (i.e., load–axis intercept, velocity–axis intercept, and area under the load–velocity relationship line) were obtained from the multiple-point (L1-L2-L3-L4) and two-point (L1-L4) methods. All load–velocity relationship variables presented greater magnitudes when obtained by the two-point method compared with the multiple-point method (p < 0.001, ES_range = 0.17–0.43), while the load–velocity relationship variables were comparable between both PBP variants (p ≥ 0.148). In addition, the load–velocity relationship variables were highly correlated between both methods (r_range = 0.972–0.995) and PBP variants (r_range = 0.798–0.909). When assessing the load–velocity relationship variables, practitioners should prescribe only two loads, as this maximises the magnitudes of the variables and decreases fatigue. Full article

This study aimed to describe the acceleration–speed (AS) profile of soccer players during competition and to analyse their seasonal changes and inter-player differences. The AS profile values (theoretical maximum acceleration (A₀) and speed (S₀)) of 14 elite soccer players were studied in 18 matches, which were divided into five season periods. The main findings showed the A₀ (6.20 ± 0.51 m/s²) and S₀ (9.18 ± 0.58 m/s) average team season values. Significant individual changes (p < 0.05 and effect size (Eta-squared, η²) > 0.5) were confirmed for A₀ (Players 4 and 8) and S₀ (Players 6, 8 and 11). Additionally, standard deviations (SD±) confirmed small (±0.20–0.60) to moderate (±0.60–1.20) seasonal variations for most players in A₀ (SD range: ±0.22 to ±0.69 m/s²) and S₀ (SD range: ±0.27 to ±0.90 m/s). SD showed small to moderate inter-player differences for each period for A₀ (SD range: ±0.39 to ±0.61 m/s²) and S₀ (SD range: ±0.53 to ±0.61 m/s). In summary, coaches are recommended to assess the AS profile to diagnose potential player seasonal changes in sprinting performance, especially for A₀, which seems to be more sensitive to variations than S₀. Full article

This review aims to synthesize and discuss the potential effects of a stack height modification on the function of the different footwear features and their effects on running performance. Peer-reviewed studies were identified from electronic databases using a structured keyword search and a screening process. Complementary sources were used to illustrate and discuss the current racing footwear constructions. With regard to the shoe mass, it is suggested that a stack height difference of 20 mm could induce a meaningful effect on performance. With respect to the midsole properties, it seems that reducing the stack height does not alter the energy returned, given that the lower midsole deformation is counteracted with an increased stiffness. However, it should be noted that this might affect the timing of the midsole deformation and restitution, which should be matched with the mid and propulsive stance phases. Lastly, the curved geometry of the forefoot sole needed to create the teeter-totter effect could be affected by the stack height reduction. However, current racing footwear designs have counteracted this modification by proximately placing the rocker axis and increasing the toe spring. Full article

Background: Despite the growing interest in golf, the impact of motion control strategy on golf performance may be uncertain. A network meta-analysis was conducted to investigate the relationships between ground reaction force (GRF), foot positions, and club types in golf and determine whether different clubs have a different impact when swinging. Methods: Three databases were searched from the time of inception to March 2023. Eligibility criteria included studies that provided data using a driver to swing and compared outcomes to control data. Results: Searches yielded 6527 studies. Seven studies met the selection criteria (n = 422 participants). The results showed that an iron 6 is the best when considering the trail foot vertical ground reaction force (TVGRF), trail foot anteroposterior ground reaction force (TAGRF), and lead foot vertical ground reaction force (LVGRF). The pitching wedge was the best in the lead foot mediolateral ground reaction force (LMGRF) and lead foot anteroposterior ground reaction force (LAGRF). Iron 7 was the best in the trail foot mediolateral ground reaction force (TMGRF), and the lead foot was larger than the trail foot to the vertical GRF. Discussion: The study found that clubs may influence a player’s posture and swing power because golf clubs are available in various lengths and shapes. The lead foot generates a larger GRF than the trail foot; three-dimensional GRFs differ among golf clubs. When a golfer aims to maximize the distance of their drives, they must generate relatively more resultant horizontal reaction force (RFH). Golfers often use different clubs to achieve optimal performance on the course by controlling their motion. However, there needs to be a focus on the quality of the included studies because the sample size was too small, increasing the risk of bias associated with the results. Full article