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Purpose: We examined the effects of two 8-week resisted-sprint training programs under different magnitudes of velocity loss (VL) on the speed-related performance of highly trained soccer players. Methods: Twenty-one soccer players (age: 25.9 [5.4] y) were randomly assigned to 1 of 2 groups: (1) the "moderate-load group," players who trained with sled loads that induced 15%VL relative to unloaded sprint velocity (n = 11); and (2) the "heavy-load group," players who trained with sled loads that induced 40% VL relative to unloaded sprint velocity (n = 10). Linear sprint (10 m), curve sprint, change-of-direction speed, resisted-sprint performance at 15% VL and 40% VL, and vertical jumping ability were tested pretraining and posttraining. A 2-way repeated-measures analysis of variance was used to test for differences between groups. In addition, percentage changes were calculated for speed-related abilities and compared with their respective coefficients of variation to determine whether individual changes in performance were greater than the test variance (ie, "true change"). Results: A main effect of time was detected for 10-m sprint, curve sprint, change-of-direction speed, and 15% VL and 40% VL resisted-sprint times, with significant decreases in sprint times (P =.003, P =.004, P =.05, P =.036, and P =.019, respectively). Jump variables did not change significantly over time. There were no group-by-time interactions for any tested variable (P >.05), but the "true change" analysis revealed meaningful individual changes in both groups. Conclusions: Both moderate- and heavy-sled loading conditions may optimize the development of speed-related abilities in highly trained soccer players. Nevertheless, resisted-sprint training responses may differ meaningfully when assessed on an individual basis. [ABSTRACT FROM AUTHOR]

Purpose: To develop gender-specific operational equations for prediction of cardiorespiratory fitness in female footballers. Method: Forty-eight semiprofessional female footballers performed an intermittent progressive maximal running test for determination of fixed blood lactate concentration (FBLC) thresholds. Relationships between FBLC thresholds and the physiological responses to submaximal running were examined. Developed equations (n = 48) were compared with equations previously obtained in another investigation performed in males (n = 100). Results: Submaximal velocity associated with 90% maximal heart rate was related to FBLC thresholds (r =.76 to.79; P <.001). Predictive power (R2 =.82 to.94) of a single blood lactate concentration (BLC) sample measured at 10 or 11.5 km·h−1 was very high. A single BLC sample taken after a 5-minute running bout at 8.5 km·h−1 was related to FBLC thresholds (r = −.71; P <.001). No difference (P =.15) in the regression lines predicting FBLC thresholds from velocity associated with 90% maximal heart rate was observed between the female and male cohorts. However, regressions estimating FBLC thresholds by a single BLC sample were different (P =.002). Conclusions: Velocity associated with 90% maximal heart rate was robustly related to FBLC thresholds and might serve for mass field testing independently of sex. BLC equations accurately predicted FBLC thresholds. However, these equations are gender-specific. This is the first study reporting operational equations to estimate the FBLC thresholds in female footballers. The use of these equations reduces the burden associated with cardiorespiratory testing. Further cross-validation studies are warranted to validate the proposed equations and establish them for mass field testing. [ABSTRACT FROM AUTHOR]

This study investigated the effects of a 11-week moderate-to-heavy sled training intervention with different magnitudes of velocity loss on sprint and jump performance, mechanical muscle function, and body composition in professional soccer players. Seventeen players (age 25.8 ± 4.3 years; height 180.0 ± 8.6 cm; mass 77.7 ± 9.7 kg) were randomly allocated into 2 groups, based on different magnitudes of velocity loss: 10% of velocity decrease (G10, n = 8) and 20% of velocity decrease (G20, n = 9). The velocity-based sled training consisted of 20-m resisted sprints with a progressive loading increase from 45 to 65% of body-mass throughout the intervention. Pre-intervention and postintervention sprint and jump performance, hamstring and quadriceps peak torque and isometric rate of torque development, and lower-limb lean mass measured by dual X-ray absorptiometry were assessed and compared. Two-way repeated measures analysis of variance revealed a significant time-effect for decreases in 10- and 20-m sprint times (p = 0.018 and p = 0.033, respectively), but without a time-group interaction. The G10 showed greater beneficial effects than G20 for both 10-m (-5.5 ± 3.3%, magnitude-based inference [MBI]: possibly vs. -1.7 ± 5.9%, MBI: possibly trivial) and 20-m (-2.5 ± 2.1%, MBI: possibly vs. -1.4 ± 3.7%, MBI: likely trivial) sprint times. Moreover, there was a significant time effect for countermovement jump height and quadriceps isometric peak torque, which decreased significantly after training (p = 0.019 and p = 0.010, respectively), with no within-group effect of time vs. group interaction for these respective outcomes. The novel velocity-based sled model proposed here, especially under lower magnitudes of velocity loss, was able to significantly improve linear sprint performance in professional soccer players. [ABSTRACT FROM AUTHOR]

Purpose: To compare the concentric and eccentric training effects on fatigue induced by eccentric and concentric protocols. Methods: A total of 22 men and women (22 [3.6] y) were assigned to concentric (GCON, n = 11) or eccentric training (GECC, n = 11). The concentric (CON) and eccentric (ECC) protocols were composed of 4 sets of 20 knee-extension/flexion repetitions. Force losses were analyzed by comparing 10 repetitions' mean torques during the protocols and by verifying the maximal voluntary contraction and rate of torque development before and after the protocols. Muscle damage was assessed using echo intensity of the vastus lateralis 48 h after the protocols. Training consisted of 6 wk of isokinetic exercise at 60°/s (concentric or eccentric) twice weekly. Results: Before training, both protocols resulted in dynamic and isometric force losses in GCON and GECC (P <.01), but the magnitude was greater after the CON protocol than after the ECC protocol (P <.001). After training, both GCON and GECC showed similar force decreases during the CON and ECC protocols (P <.01), and these changes were not different from the pretraining decreases. Regarding maximal voluntary contraction after training, GECC showed lower force decreases than GCON after ECC exercise (−13.7% vs −22.3%, respectively, P <.05), whereas GCON showed lower maximal voluntary contraction decreases after CON exercise compared with pretraining (−29.2%, P <.05). Losses in rate of torque development were similar after the protocols before and after the training regimens. No changes in echo intensity were observed after the protocols before and after training. Conclusion: Both interventions resulted in similar force decreases during fatigue protocols compared with those associated with pretraining. [ABSTRACT FROM AUTHOR]

Context: The muscular function restoration related to the type of physical rehabilitation followed after anterior cruciate ligament reconstruction (ACLR) using autologous hamstring tendon graft in terms of strength and cross-sectional area (CSA) remain controversial. Objective: To analyze the CSA and force output of quadriceps and hamstring muscles in subjects following either an Objective Criteria-Based Rehabilitation (OCBR) algorithm or the usual care (UCR) for ACL rehabilitation in Spain, before and 1 year after undergoing an ACLR. Design: Longitudinal clinical double-blinded randomized controlled trial. Setting: Sports-medicine research center. Patients: 40 recreational athletes (30 male, 10 female [24 ± 6.9 y, 176.55 ± 6.6 cm, 73.58 ± 12.3 kg]). Intervention: Both groups conducted differentiated rehabilitation procedures after ACLR. Those belonging to OCBR group were guided in their recovery according to the current evidence-based principles. UCR group followed the national conventional approach for ACL rehabilitation. Main Outcome Measures: Concentric isokinetic knee joint flexor-extension torque assessments at 180°/s and Magnetic Resonance Imaging (MRI) evaluations were performed before and 12 months after ACLR. Anatomical muscle CSA (mm²) was assessed, in Quadriceps, Biceps femoris, Semitendinous, Semimembranosus, and Gracilis muscles at 50% and 70% femur length. Results: Reduced muscle CSA was observed in both treatment groups for Semitendinosus and Gracilis 1 year after ACLR. At 1-year follow-up, subjects allocated to the OCBR demonstrated greater knee flexor and extensor peak torque values in their reconstructed limbs in comparison with patients treated by UCR. Conclusions: Objective atrophy of Semitendinosus and Gracilis muscles related to surgical ACLR was found to persist in both rehabilitation groups. However, OCBR after ACLR lead to substantial gains on maximal knee flexor strength and ensured more symmetrical anterior-posterior laxity levels at the knee joint. [ABSTRACT FROM AUTHOR]

Context • Alternatives to medication for immediate pain relief are needed because long-term use of pain medication has been associated with adverse effects. High-velocity, low-amplitude (HVLA) manipulation techniques (MTs) and craniocervical flexion (CCF) exercises have been frequently used in the management of chronic cervical pain. Objective • The study intended to compare the immediate effects on pain of a treatment using HVLA manipulation versus one using a CCF exercise protocol. Design • The research team designed a single-blinded, randomized clinical trial. Setting • The study was conducted at osteopathic clinics. Participants • Participants were 25 volunteer patients with chronic neck pain. Intervention • Participants were randomly enrolled in one of 2 groups: the HVLA manipulation group (MT group), n = 12, or the CCF exercise protocol group (CCF group), n = 13. Participants in the CCF group performed the exercise for 10 repetitions of a 10-s duration, with a 10-s rest interval between each contraction, for a total contraction time of 100 s and a total time of the session of 190 s. Outcome Measures • The outcomes were measured at baseline and at 60 s postintervention. The measures included (1) a visual analogue scale (VAS) completed during range of motion (ROM) measurement, (2) an evaluation of the ROM of the cervical spine, (3) a test of pressure pain thresholds (PPTs), and (4) electromyographic (EMG) activation of sternocleidomastoid muscle during a craniocervical flexion test. Results • Following both interventions, significant changes were found between baseline and immediately postintervention in the VAS score during ROM measurement for both groups, with P = .004 and P = .015, respectively. In the MT group, the measures for flexion (P = .001), right-side bending (P = .002), and left rotation (P = .005) changed significantly between baseline and postintervention; however, only flexion (P = .026) and extension (P = .040) ROM changed significantly between baseline and postintervention in the CCF group. Significant changes were observed in upper trapezius PPT following both interventions-MT group, P = .043, and CCF group, P = .005. In addition, significant changes in C5 PPT had occurred in the CCR group (P = .020). Between-group differences were significant for extension and right-side-bending ROM, with P = .019 and P = .012, respectively, and the changes between baseline and postintervention were greater in the MT group. None of the interventions led to changes in EMG. Conclusions • Although both interventions were associated with immediately improved ROM and pain after treatment, HVLA manipulation was more effective than CCF exercise in improving ROM and VAS during ROM. None of the interventions led to changes in EMG. [ABSTRACT FROM AUTHOR]

Context • Alternatives to medication for immediate pain relief are needed because long-term use of pain medication has been associated with adverse effects. High-velocity, low-amplitude (HVLA) manipulation techniques (MTs) and craniocervical flexion (CCF) exercises have been frequently used in the management of chronic cervical pain. Objective • The study intended to compare the immediate effects on pain of a treatment using HVLA manipulation versus one using a CCF exercise protocol. Design • The research team designed a single-blinded, randomized clinical trial. Setting • The study was conducted at osteopathic clinics. Participants • Participants were 25 volunteer patients with chronic neck pain. Intervention • Participants were randomly enrolled in one of 2 groups: the HVLA manipulation group (MT group), n = 12, or the CCF exercise protocol group (CCF group), n = 13. Participants in the CCF group performed the exercise for 10 repetitions of a 10-s duration, with a 10-s rest interval between each contraction, for a total contraction time of 100 s and a total time of the session of 190 s. Outcome Measures • The outcomes were measured at baseline and at 60 s postintervention. The measures included (1) a visual analogue scale (VAS) completed during range of motion (ROM) measurement, (2) an evaluation of the ROM of the cervical spine, (3) a test of pressure pain thresholds (PPTs), and (4) electromyographic (EMG) activation of sternocleidomastoid muscle during a craniocervical flexion test. Results • Following both interventions, significant changes were found between baseline and immediately postintervention in the VAS score during ROM measurement for both groups, with P = .004 and P = .015, respectively. In the MT group, the measures for flexion (P = .001), right-side bending (P = .002), and left rotation (P = .005) changed significantly between baseline and postintervention; however, only flexion (P = .026) and extension (P = .040) ROM changed significantly between baseline and postintervention in the CCF group. Significant changes were observed in upper trapezius PPT following both interventions—MT group, P = .043, and CCF group, P = .005. In addition, significant changes in C5 PPT had occurred in the CCR group (P = .020). Between-group differences were significant for extension and right-side-bending ROM, with P = .019 and P = .012, respectively, and the changes between baseline and postintervention were greater in the MT group. None of the interventions led to changes in EMG. Conclusions • Although both interventions were associated with immediately improved ROM and pain after treatment, HVLA manipulation was more effective than CCF exercise in improving ROM and VAS during ROM. None of the interventions led to changes in EMG. [ABSTRACT FROM AUTHOR]

Persistent biomechanical and jumping capacity alterations have been observed among female athletes who have sustained anterior cruciate ligament (ACL) injuries. The purpose of this study was to examine if biomechanical jumping differences persist among a cohort of elite female handball players with previous ACL reconstruction several years after return to top-level competition. In order to achieve this goal, a direct mechanics simplified analysis by using a single Inertial Sensor Unit (IU) was used. Twenty-one elite female (6 anterior cruciate ligament reconstructed and 15 uninjured control players) handball players were recruited and evaluated 6.0 ± 3.5 years after surgical anterior cruciate ligament reconstruction. Bilateral and unilateral vertical jumps were performed to evaluate the functional performance and a single inertial sensor unit was employed in order to collect 3D acceleration and 3D orientation data. Previously ACL-reconstructed analysed athletes demonstrated significant (p < 0.05) alterations in relation to the three-dimensional axis (X–Y–Z) supported accelerations and differing jump phase durations, including jumping performance values, in both bilateral and unilateral jumping manoeuvres several years after ACL reconstruction. Identification of the encountered deficits through the use of an IU devise could provide clinicians with a new reliable tool for movement analysis in a clinical setting. [ABSTRACT FROM PUBLISHER]

This study investigated the associations between pre-season and in-season performance with external workload in professional soccer players. Twenty-one players completed hamstring strength, countermovement jump (CMJ), 20-m sprint, and Yo-Yo intermittent recovery tests before (pre-season) and after 8 weeks (in-season). External workload (total distance, high-intensity running distance, number of sprints, and power plays) was quantified during this period, and used to divide the average above and below subgroups outcome by outcome for further analyses. Significance was accepted when P≤0.05. Hamstring strength declined from pre- to in-season [- 6%; p=0.014; effect size (ES): - 0.41], while Yo-Yo performance improved (46%; p=0.001; ES: 1.31). When divided by high-intensity running distance, only the below-average subgroup improved CMJ performance (5%; p=0.030). For minutes played, the above-average subgroup improved Yo-Yo performance (41%; p<0.001), but not the below-average subgroup. Furthermore, playing time correlated with improved Yo-Yo performance (p=0.040; r=0.534). Improved 20-m sprint performance associated with more sprints performed (p=0.045; r=- 0.453). Physical capabilities changed over a competitive season and were related to, and differentiated by, external workload. Because hamstring strength decreased and CMJ only improved in players exposed to less high-intensity external load, practitioners should individualize approaches to counteract these conditions when high external workload is performed over the season., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Purpose: To identify the physical conditioning and functional injury-screening characteristics of elite female soccer players., Methods: This review was prospectively registered (PROSPERO CRD4202346765). Searches were conducted in PubMed/MEDLINE, Cochrane Library, Scopus, and Web of Science (from inception in March 2023 to July 2023). Updated searches were conducted in October 2023 and April 2024. Included studies were quantitative studies conducted on female soccer players. Main outcomes were functional and physical profiles. Screening, data extraction, and quality assessment (Quality Assessment Tool for Quantitative Studies and the Oxford Levels of Evidence scales) were performed. Mean differences between preseason and in-season testing periods were estimated by Hedges g effect size. Methods and results were reported according to PRISMA guidelines., Results: The search yielded 1727 articles, of which 10 were included. Overall methodological quality of the studies was strong, with a moderate level of evidence. Players exhibited mean maximal oxygen uptake of 52.6 (4.5) mL·min-1·kg-1, 20-m linear-sprint performance of 3.58 (0.18) seconds, countermovement jump of 31.0 (2.9) cm, unilateral countermovement jump of 14.4 (2.1) cm, and quadriceps and hamstring peak torque at 60°·s-1 of 133 (23) and 87 (17) N·m, respectively. Mean scores recorded during in-season were 2% to 22% better than in preseason (effect size: small to very large)., Conclusions: This review provides valuable normative physical conditioning and functional injury-risk assessment data for elite female soccer players. Coaches and conditioning staff can use these insights to interpret their own records and optimize their training processes. Furthermore, this study identifies methodological limitations to address in future research.

Background: Volleyball is a complex intermittent sport characterized by short explosive technical movements, many of which involve vertical jumping. The assessment of mechanical jumping variables in relation to both injury prevention and performance enhancement through the use of wearable technologies is becoming a new training tool among professional volleyball players., Methods: The present study aimed to assess the vertical jumping mechanics before and after a controlled load (volume and intensity) of a routine volleyball training session among male professional players. Twelve male elite professional volleyball players (23.7±4.9 years, 198.1±6.2 cm, 92.2±10.3 kg) of national and international level belonging to the same Brazilian first league team were recruited. Biomechanical analysis of vertical unilateral countermovement jump (CMJ) and bilateral CMJ tests were performed before and after a routine training session of these players at their usual training court. An inertial orientation sensor placed at the third lumbar vertebra was employed for biomechanical data collection., Results: In relation to the unilateral CMJ, a 10% decrease (P=0.02) in the vertical ground reaction force after training compared to pretraining values was observed. However, no significant differences were observed in the remaining outcomes. Regarding the bilateral CMJ, no significant differences were observed in all assessed outcomes., Conclusions: Our findings showed no evidence of fatigue after a controlled regular in season volleyball training session in professional players. In addition, this volleyball training session induced a significant reduction in the vertical ground reaction force during unilateral CMJ in volleyball players.