The contribution of the tendon electrode to M-wave characteristics in the biceps brachii, vastus lateralis and tibialis anterior.

In some compound muscle action potentials (M waves) recorded using the belly-tendon configuration, the tendon electrode makes a noticeable contribution to the M wave. However, this finding has only been demonstrated in some hand and foot muscles. Here, we assessed the contribution of the tendon potential to the amplitude of the vastus lateralis, biceps brachii and tibialis anterior M waves, and we also examined the role of this tendon potential in the shoulder-like feature appearing in most M waves. M waves were recorded separately at the belly and tendon locations of the vastus lateralis, biceps brachii and tibialis anterior from 38 participants by placing the reference electrode at a distant (contralateral) site. The amplitude of the M waves and the latency of their peaks and shoulders were measured. In the vastus lateralis, the tendon potential was markedly smaller in amplitude (∼75%) compared to the belly M wave (P = 0.001), whereas for the biceps brachii and tibialis anterior, the tendon and belly potentials had comparable amplitudes. In the vastus lateralis, the tendon potential showed a small positive peak coinciding in latency with the shoulder of the belly-tendon M wave, whilst in the biceps brachii and tibialis anterior, the tendon potential showed a clear negative peak which coincided in latency with the shoulder. The tendon potential makes a significant contribution to the belly-tendon M waves of the biceps brachii and tibialis anterior muscles, but little contribution to the vastus lateralis M waves. The shoulder observed in the belly-tendon M wave of the vastus lateralis is caused by the belly potential, the shoulder in the biceps brachii M wave is generated by the tendon potential, whereas the shoulder in the tibialis anterior M wave is caused by both the tendon and belly potentials. NEW FINDINGS: What is the central question of this study? Does a tendon electrode make a noticeable contribution to the belly-tendon M wave in the vastus lateralis, biceps brachii and tibialis anterior muscles? What is the main finding and its importance? Because the patellar tendon potential is small in amplitude, it hardly influences the amplitude and shape of the belly-tendon M wave of the vastus lateralis. However, for the biceps brachii and tibialis anterior muscles, the potentials at the tendon sites show a large amplitude, and thus have a great impact on the corresponding belly-tendon M waves.

Speed-Related Abilities Are Similarly Improved After Sled Training Under Different Magnitudes of Velocity Loss in Highly Trained Soccer Players.

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.

Effects of Moderate-to-Heavy Sled Training Using Different Magnitudes of Velocity Loss in Professional Soccer Players.

ABSTRACT: Grazioli, R, Loturco, I, Lopez, P, Setuain, I, Goulart, J, Veeck, F, Inácio, M, Izquierdo, M, Pinto, RS, and Cadore, EL. Effects of moderate-to-heavy sled training using different magnitudes of velocity loss in professional soccer players. J Strength Cond Res 37(3): 629-635, 2023-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.

The influence of the reference electrode location on the M-wave characteristics in the quadriceps.

INTRODUCTION: In the compound muscle action potential (M wave) recorded using the belly-tendon configuration, the contribution of the tendon electrode is assumed to be negligible compared to the belly electrode. We tested this assumption by placing the reference electrode at a distant (contralateral) site, which allowed separate recording of the belly and tendon contributions. METHODS: M waves were recorded at multiple selected sites over the right quadriceps heads and lower leg using two different locations for the reference electrode: the ipsilateral (right) and contralateral (left) patellar tendon. The general parameters of the M wave (amplitude, area, duration, latency, and frequency) were measured. RESULTS: (1) The tendon potential had a small amplitude (<30%) compared to the belly potential; (2) Changing the reference electrode from the ipsilateral to the contralateral patella produced moderate changes in the M wave recorded over the innervation zone, these changes affecting significantly the amplitude of the M-wave second phase (p = 0.006); (3) Using the contralateral reference system allowed recording of short-latency components occurring immediately after the stimulus artefact, which had the same latency and amplitude (p = 0.18 and 0.25, respectively) at all recording sites over the leg. CONCLUSIONS: The potential recorded at the "tendon" site after femoral nerve stimulation is small (compared to the belly potential), but not negligible, and makes a significant contribution to the second phase of belly-tendon M wave. Adopting a distant (contralateral) reference allowed recording of far-field components that may aid in the understanding of the electrical formation of the M wave.

Jump performance and mechanics after a regular training bout in elite volleyball players.

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.

Predicting Cardiorespiratory Fitness in Female Soccer Players: The Basque Female Football Cohort Study.

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.

Functional and Anthropometrical Screening Test among High Performance Female Football Players: A Descriptive Study with Injury Incidence Analysis, the Basque Female Football Cohort (BFFC) Study.

The main objectives of the present study were to describe the injury incidence and to analyze the anthropometric and physical characteristics of players from three high-level women's football teams. The present study involved 54 female football players (21.9 ± 4.9 years old) from three different teams competing in the Spanish Reto Iberdrola-Segunda División PRO league. A battery of tests was carried out to determine the anthropometric and physical performance characteristics of the players along with an injury incidence record during a full competitive season. The obtained results showed that there was a high incidence of injury, as 38% of the players suffered some type of injury during the season (range 1-5; 1.75 ± 1.02 injuries per player). Injuries occurred in both matches and during training at a similar percentage (48.6 vs. 51.4%), and the majority of the registered episodes were graded as moderate or severe injury types (60%). Players suffering from an injury accumulated a total of 1587 chronological days off work due to injury during the season, with a recurrence rate of 55%. Considering the high incidence of injury, and the injury burden and the reinjure rate observed in this research, it seems necessary to apply the most efficient prevention and recovery measures possible in these female football teams. These descriptive data could serve athletic trainers and medical staff of female football teams to better understand their own screening procedure-derived data.

Moderate volume of sprint bouts does not induce muscle damage in well-trained athletes.

INTRODUCTION: Understanding the recovery in response to different sprint protocols is important for optimizing neuromuscular gains and organizing training sessions in sports. The current study aimed to investigate acute neuromuscular changes following a moderate volume of sprint protocols with and without change-of-direction. METHODS: 26 well-trained male collegiate athletes from different sports were randomly allocated into straight-line group (SLG) or change-of-direction group (CODG). The protocols were 1 × 15 repetitions of 20-meter sprints in line (SLG) or with two changes in each repetition (CODG). Knee extension maximal and explosive strength, jump performance, serum creatine kinase, and quadriceps and hamstrings echo intensity were collected pre-, post- 0, 24, 48, and 72 h post-exercise. RESULTS: There were no significant changes in any of the variables at any time point after the exercise protocols in comparison with pre-exercise values (p > 0.05). CONCLUSIONS: The present study suggests that sprint training with moderate volume with or without change of direction does not induce neuromuscular or physiological changes during 72 h post-exercise. This information is especially important for sports staff in order to optimize training prescription and frequency.

Horizontal jumping biomechanics among elite female handball players with and without anterior cruciate ligament reconstruction: an ISU based study.

BACKGROUND: Handball is a strenuous body-contact team sport that places high loads on the knee joint. Anterior cruciate ligament (ACL) tear is one of the most devastating injuries that any handball player can suffer, and female athletes are at particular risk due to their intrinsic anatomical, hormonal, neuromuscular and biomechanical characteristics. The purpose of this study was to analyze the horizontal jumping biomechanics of female elite handball players with or without previous ACL reconstruction. METHODS: Twenty-one female participants (6 with previous ACL reconstruction and 15 uninjured controls) were recruited. Two horizontal hopping tasks were evaluated using inertial sensor unit (ISU)-based technology to assess jumping biomechanics through a direct mechanics-based approach. RESULTS: The athletes with previous ACL reconstruction demonstrated a significant (P < 0.05) reduction in the unilateral triple hop for distance compared with the healthy controls. Furthermore, during the initial propulsive phase of the unilateral cross-over hop, the control participants generated significantly (P < 0.05) higher force values in the mediolateral direction (the X axis) with their dominant limb compared with the ACL-reconstructed (ACL-R) limb of previously injured participants. CONCLUSIONS: Three-dimensional horizontal jumping biomechanics analyses using ISU-based technologies could provide clinicians with more accurate information regarding the horizontal jumping biomechanical patterns among elite handball female athletes. Furthermore, several mechanical alterations could still be observed among those players who had undergone previous ACL reconstruction, even when several years have passed since the original ACL injury.

Horizontal jumping biomechanics among elite male handball players with and without anterior cruciate ligament reconstruction. An inertial sensor unit-based study.

OBJECTIVES: Anterior cruciate ligament (ACL) tears are one of the most devastating injuries that any handball player can suffer during landing and pivoting actions. The aim of this study was to analyze the horizontal jumping biomechanics among male elite handball players with or without previous ACLR. DESIGN: Descriptive study. SETTING: Spanish elite male handball players. PARTICIPANTS: Twenty-six male participants (6 ACL-R and 20 uninjured controls) were recruited. MAIN OUTCOME MEASURES: Two horizontal hopping tasks were evaluated using an inertial sensor unit (ISU)-based technology to assess jumping biomechanics through a direct mechanics-based approach. RESULTS: Non-significant differences were found in relation to any of the biomechanical or performance related analyzed variables. CONCLUSIONS: Previously ACL-R elite male handball players who have returned to the top level of sports participation do not seem to possess lasting biomechanical and/or performance deficits 6 years after the original surgical ligament repair.

Effects of Concentric and Eccentric Strength Training on Fatigue Induced by Concentric and Eccentric Exercises.

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.

Short-term effects of manipulative treatment versus a therapeutic home exercise protocol for chronic cervical pain: A randomized clinical trial.

BACKGROUND: While both manipulative treatment and physical exercises are used to treat cervical pain, it remains unclear which is most effective. OBJECTIVE: To compare the short-term effects of high-velocity, low-amplitude manipulation techniques (MT) with those of home-exercise (HE) with stretching and low-intensity (10% of max) isometric contractions on pain and function. METHODS: Single-blind randomized clinical trial was performed. A total of 27 asymptomatic subjects were randomly assigned to 2 groups: manipulation techniques (MT, n= 13) and home exercise (HE, n= 14). The visual analogue scale (VAS); neck disability index (NDI); pressure pain thresholds; cervical spine range of motion and electromyography during the cranio-cervical flexion test was measured before and one week after the intervention. RESULTS: After the intervention, both groups showed improved (P< 0.05) NDI and VAS scores and flexion in both rotation ranges compared with the pre-intervention values. For the NDI, pain intensity, and neck flexion, the effects sizes were large; for the majority of the other measurements, the effect sizes were small to moderate. The MT group showed significantly better results than the HE group for 2 out of 17 tests. CONCLUSIONS: Both interventions improved function and pain after one week, with only marginal between-group differences in favor of MT.

Immediate Effects of Osteopathic Treatment Versus Therapeutic Exercise on Patients With Chronic Cervical Pain.

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.

Sprint mechanics return to competition follow-up after hamstring injury on a professional soccer player: A case study with an inertial sensor unit based methodological approach.

BACKGROUND: The present research aimed to describe an inertial unit (IU)-based sprint mechanics evaluation model for assessing players' readiness to return to competition after suffering a grade I hamstring injury. METHODS: A professional male football player (age 19years; height 177cm; weight 70kg, midfielder, Spanish, 3° Division) with a grade 1 biceps femoris injury was evaluated at pre-season, at return to play after injury and at the end of the competitive season. Sprint mechanics were analyzed via the use of an inertial orientation tracker (Xsens Technologies B.V. Enschede, Netherlands) attached over the L3-L4 region of the subject's lumbar spine. Sprint mechanics such as horizontal components of ground reaction force were assessed in both legs during sprinting actions. Findings and interpretation: Both the coefficient of the horizontal force application (SFV) and the ratio of forces (DRF) applied at increasing velocity were decreased in the injured limb compared with the contralateral healthy limb at the return to play evaluation (73% and 76% reductions, respectively) and returned to symmetrical levels at the end-season evaluation.

Effects of Cervical High-Velocity Low-Amplitude Techniques on Range of Motion, Strength Performance, and Cardiovascular Outcomes: A Review.

BACKGROUND: Cervical high-velocity low-amplitude (HVLA) manipulation technique is among the oldest and most frequently used chiropractic manual therapy, but the physiologic and biomechanics effects were not completely clear. OBJECTIVE: This review aims to describe the effects of cervical HVLA manipulation techniques on range of motion, strength, and cardiovascular performance. METHODS/DESIGN: A systematic search was conducted of the electronic databases from January 2000 to August 2016: PubMed (n = 131), ScienceDirect (n = 101), Scopus (n = 991), PEDro (n = 33), CINAHL (n = 884), and SciELO (n = 5). Two independent reviewers conducted the screening process to determine article eligibility. The intervention that included randomized controlled trials was thrust, or HVLA, manipulative therapy directed to the cervical spine. Methodological quality was assessed using the Cochrane risk-of-bias tool. The initial search rendered 2145 articles. After screening titles and abstracts, 11 articles remained for full-text review. RESULTS: The review shows that cervical HVLA manipulation treatment results in a large effect size (d > 0.80) on increasing cervical range of motion and mouth opening. In patients with lateral epicondylalgia, cervical HVLA manipulation resulted in increased pain-free handgrip strength, with large effect sizes (1.44 and 0.78, respectively). Finally, in subjects with hypertension the blood pressure seemed to decrease after cervical HVLA manipulation. Higher quality studies are needed to develop a stronger evidence-based foundation for HVLA manipulation techniques as a treatment for cervical conditions.

A protocol for a new methodological model for work-related shoulder complex injuries: From diagnosis to rehabilitation.

BACKGROUND: Work-related injuries of the shoulder complex represent a challenge for clinicians because of the large variety of clinical entities involved and the broad anatomic structures that can be affected. Furthermore, commonly performed orthopedic tests have demonstrated limited accuracy for diagnosing the injury despite considerable research efforts. The aim of this study protocol is therefore to describe a comprehensive approach integrating both a clinical- and functional status-based pathology and an adapted rehabilitation prescription. METHODS/DESIGN: A longitudinal cohort study will be performed at the Department of Rehabilitation and Medical Assistance of a mutual insurance society for work-related injury management in Spain (Mutua Navarra, Pamplona, Navarra Spain). Patients will be attended by an occupational physician who specializes in work-related injuries and is part of the project team that will systematically visit all the participants. After the medical diagnosis and any requested supplementary evaluations (i.e., radiological examinations), the patients will be referred to the rehabilitation service. Before the physiotherapeutic rehabilitation program is initiated, the patients will undergo a comprehensive functional screening at the biomechanics laboratory. Using a decision-making scheme, the identified functional deficits will be used to customize the individual rehabilitation plan. DISCUSSION: The proposed objective criteria-based shoulder diagnosis and rehabilitation model could be a new effective strategy for minimizing the time required to regain functional capacity and recover from symptoms among patients with work-related shoulder injuries. TRIAL REGISTRATION: The study protocol has been registered on Clinical Trials.gov as NCT02732002 (April 10th 2016).

Differential Effects of 2 Rehabilitation Programs Following Anterior Cruciate Ligament Reconstruction.

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.

Biomechanical jumping differences among elite female handball players with and without previous anterior cruciate ligament reconstruction: a novel inertial sensor unit study.

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.

Acceleration and Orientation Jumping Performance Differences Among Elite Professional Male Handball Players With or Without Previous ACL Reconstruction: An Inertial Sensor Unit-Based Study.

BACKGROUND: Handball is one of the most challenging sports for the knee joint. Persistent biomechanical and jumping capacity alterations can be observed in athletes with an anterior cruciate ligament (ACL) injury. Commonly identified jumping biomechanical alterations have been described by the use of laboratory technologies. However, portable and easy-to-handle technologies that enable an evaluation of jumping biomechanics at the training field are lacking. OBJECTIVE: To analyze unilateral/bilateral acceleration and orientation jumping performance differences among elite male handball athletes with or without previous ACL reconstruction via a single inertial sensor unit device. DESIGN: Case control descriptive study. SETTING: At the athletes' usual training court. PARTICIPANTS: Twenty-two elite male (6 ACL-reconstructed and 16 uninjured control players) handball players were evaluated. METHODS: The participants performed a vertical jump test battery that included a 50-cm vertical bilateral drop jump, a 20-cm vertical unilateral drop jump, and vertical unilateral countermovement jump maneuvers. MAIN OUTCOME MEASUREMENTS: Peak 3-dimensional (X, Y, Z) acceleration (m·s(-2)), jump phase duration and 3-dimensional orientation values (°) were obtained from the inertial sensor unit device. Two-tailed t-tests and a one-way analysis of variance were performed to compare means. The P value cut-off for significance was set at P < .05. RESULTS: The ACL-reconstructed male athletes did not show any significant (P < .05) residual jumping biomechanical deficits regarding the measured variables compared with players who had not suffered this knee injury. A dominance effect was observed among non-ACL reconstructed controls but not among their ACL-reconstructed counterparts (P < .05). CONCLUSIONS: Elite male handball athletes with previous ACL reconstruction demonstrated a jumping biomechanical profile similar to control players, including similar jumping performance values in both bilateral and unilateral jumping maneuvers, several years after ACL reconstruction. These findings are in agreement with previous research showing full functional restoration of abilities in top-level male athletes after ACL reconstruction, rehabilitation and subsequent return to sports at the previous level.