Tibiofemoral bone configuration is not associated with hamstring muscle strength in male and female patients with ACL reconstruction.

PURPOSE: Previous evidence indicated that the tibiofemoral bone configuration might elevate the risk of an anterior cruciate ligament (ACL) injury. Furthermore, a low hamstring-to-quadriceps muscle ratio predisposes especially females to unfavourable knee kinematics. The primary objective of the present study was to investigate sex-specific associations between tibiofemoral bone geometry and isokinetic knee flexion torque in patients with primary ACL injury followed by ACL reconstruction. METHODS: N = 100 patients (72 = male, 28 = female, age = 31.3 ± 10.2, body mass index = 25.3 ± 3.6) with primary ACL rupture with isokinetic knee flexion torque assessments before and 6 months after ACL reconstruction surgery were analysed. Magnetic resonance imaging scans were analysed for medial posterior tibial slope (MPTS) and lateral posterior tibial slope, notch width index (NWI) and lateral femoral condyle index (LFCI). Additionally, isokinetic knee flexion torque (60°/s) and hamstring-quadriceps ratios were evaluated. Subsequently, functional parameters were correlated with imaging data for gender subgroups. RESULTS: The findings showed that presurgical isokinetic knee flexion torque was not associated with any marker of femoral or tibial bone geometry. Further, while significant differences were observed between female (0.883 ± 0.31 Nm/kg) and male (1.18 ± 0.35 Nm/kg) patients regarding preoperative normalized knee flexion torque (p < 0.001), no significant sex differences were found for percentage increases in normalized knee flexion torque from presurgery to postsurgery. Generally, female patients demonstrated significantly higher MPTS magnitudes (p < 0.05) and lower LFCI values (p < 0.05) compared to men. CONCLUSION: The present results demonstrated no association between tibial or femoral bone geometry and muscle strength of the hamstrings in patients with ACL reconstruction, indicating an important mismatch of muscular compensation to deviations in bone geometry. There were no sex-specific differences in tibiofemoral bone parameters. LEVEL OF EVIDENCE: Level III.

Effects of arthroscopic rotator cuff repair on isokinetic muscle function 6-months following surgery: influence of tear type, tear size and tendon retraction.

BACKGROUND: Rotator cuff tears are a common musculoskeletal condition which can lead to functional limitations and impairments in quality of life. The purpose of the present study was to investigate the effects of arthroscopic repair surgery on isokinetic muscle function before and 6-months after surgery. Additionally, the mediating effects of tear type, tear size and tendon retraction were examined. METHODS: Data from n = 67 patients (56 ± 9 years) with full-thickness rotator cuff tears were analyzed. Before and 6-months after surgery, isokinetic muscle function in external/internal rotation and abduction/adduction movements was assessed. Further, tear size, tear type (Collin classification) and tendon retraction (Patte classification) were analyzed using magnetic resonance imaging (MRI). RESULTS: After statistical analysis, a significant increase in limb symmetry index (LSI) of external (p < 0.001), internal rotation (p < 0.01), abduction (p < 0.001) and adduction (p < 0.001) were observed from pre- to post-surgery. The results revealed that tear size and tendon tear type significantly mediated the functional outcome, with no significant effect of tendon retraction. CONCLUSION: The present findings point towards the notion that the functional outcome following rotator cuff repair was significantly dependent on tear type and tear size but not tendon retraction. Patients with larger sized tears presented pronounced deficits following 6-months indicating that rehabilitation times need to be adjusted accordingly.

Effects of transcranial direct current stimulation and sensorimotor training in anterior cruciate ligament patients: a sham-controlled pilot study.

BACKGROUND: Studies showed changes in the central nervous system in patients who sustained an anterior cruciate ligament tear. There is a lack of evidence regarding the effectiveness of transcranial direct-current stimulation in such patients. METHODS: A sham-controlled randomised study. One group of patients (n = 6) underwent 6 weeks of sensorimotor training after an anterior cruciate ligament tear during transcranial direct-current stimulation. The stimulation consisted of 20 minutes (3 sessions/week; 2 weeks) of 2 mA anodal transcranial direct-current stimulation over the primary motor and premotor cortex. The second group (n = 6) received sham stimulation with 6 weeks of sensorimotor training. Centre of pressure deviations in the medio-lateral and anterior-posterior direction and centre of pressure velocity were measured. RESULTS: The results demonstrated a significant effect of sensorimotor training on the centre of pressure in medio-lateral and anterior-posterior direction (p=0.025) (p=0.03) in the leg in which an anterior cruciate ligament tear occurred. The type of training did not affect the results. Post-hoc tests showed no significant effect of training in the subgroups (p≥0.115). CONCLUSION: Sensorimotor training led to a decrease in sway of the centre of pressure in patients who sustained an anterior cruciate ligament tear, but the addition of anodal transcranial direct-current stimulation placed over the primary motor cortex did not potentiate the adaptive responses of the sensorimotor training.

Idiosyncratic bone responses to blood flow restriction exercise: new insights and future directions.

Applying blood flow restriction (BFR) during low-load exercise induces beneficial adaptations of the myotendinous and neuromuscular systems. Despite the low mechanical tension, BFR exercise facilitates a localized hypoxic environment and increase in metabolic stress, widely regarded as the primary stimulus for tissue adaptations. First evidence indicates that low-load BFR exercise is effective in promoting an osteogenic response in bone, although this has previously been postulated to adapt primarily during high-impact weight-bearing exercise. Besides studies investigating the acute response of bone biomarkers following BFR exercise, first long-term trials demonstrate beneficial adaptations in bone in both healthy and clinical populations. Despite the increasing number of studies, the physiological mechanisms are largely unknown. Moreover, heterogeneity in methodological approaches such as biomarkers of bone metabolism measured, participant and study characteristics, and time course of measurement renders it difficult to formulate accurate conclusions. Furthermore, incongruity in the methods of BFR application (e.g., cuff pressure) limits the comparability of datasets and thus hinders generalizability of study findings. Appropriate use of biomarkers, effective BFR application, and befitting study design have the potential to progress knowledge on the acute and chronic response of bone to BFR exercise and contribute toward the development of a novel strategy to protect or enhance bone health. Therefore, the purpose of the present synthesis review is to 1) evaluate current mechanistic evidence; 2) discuss and offer explanations for similar and contrasting data findings; and 3) create a methodological framework for future mechanistic and applied research.

Effects of a Web-Based Lifestyle Intervention on Physical Fitness and Health in Physically Inactive Adults: A Randomized Controlled Trial.

Web-based lifestyle interventions are a new area of health research. This randomized controlled trial evaluated the effectiveness of an interactive web-based health program on physical fitness and health. N = 189 healthy adults participated in a 12-week interactive (intervention) or non-interactive (control) web-based health program. The intervention provided a web-based lifestyle intervention to promote physical activity and fitness through individualized activities as part of a fully automated, multimodal health program. The control intervention included health information. Cardiorespiratory fitness measured as maximum oxygen uptake (VO2max) was the primary outcome, while musculoskeletal fitness, physical activity and dietary behavior, and physiological health outcomes were assessed as secondary outcomes (t0: 0 months, t1: 3 months, t2: 9 months, t3: 15 months). Statistical analysis was performed with robust linear mixed models. There were significant time effects in the primary outcome (VO2max) (t0-t1: p = 0.018) and individual secondary outcomes for the interactive web-based health program, but no significant interaction effects in any of the outcomes between the interactive and non-interactive web-based health program. This study did not demonstrate the effectiveness of an interactive compared with a non-interactive web-based health program in physically inactive adults. Future research should further develop the evidence on web-based lifestyle interventions.

Effects of Specific Bioactive Collagen Peptides in Combination with Concurrent Training on Running Performance and Indicators of Endurance Capacity in Men: A Randomized Controlled Trial.

BACKGROUND: First evidence indicates that the supplementation of specific collagen peptides (SCP) is associated with a significant improvement in running performance in physically active women; however, it is unclear if the same is true in males. The purpose of the present study was to investigate the effects of a concurrent training program including 60 min of continuous moderate intensity running training and 15 min of dynamic resistance training combined with supplementation of SCP on parameters of running performance in moderately trained males. METHODS: In a double-blind, placebo-controlled, randomized trial, participants performed a 12 weeks concurrent training and ingested 15 g of SCP [treatment group (TG)] or placebo [control group (CG)] daily. Before and after the intervention, running endurance performance was measured by a 1-h time trial on a running track. Velocity at the lactate threshold (VLT) and at the individual anaerobic threshold (VIAT) were assessed on a treadmill ergometer. Body composition was evaluated by bioelectrical impedance analysis. RESULTS: Thirty-two men (28.4 ± 5.2 years) completed the study and were included in the analysis. After 12 weeks, TG had a statistically significant (p ≤ 0.05) higher increase in running distance (1727 ± 705 m) compared to the CG (1018 ± 976 m) in the time trial. VLT increased in the TG by 0.680 ± 1.27 km h-1 and slightly decreased by - 0.135 ± 0.978 km h-1 in the CG, resulting in statistically significant group differences (p ≤ 0.05). A significantly higher improvement in VIAT (p ≤ 0.05) was shown in the TG compared with the CG only (1.660 ± 1.022 km h-1 vs 0.606 ± 0.974 km h-1; p ≤ 0.01). Fat mass decreased (TG - 1.7 ± 1.6 kg; CG - 1.2 ± 2.0 kg) and fat free mass increased (TG 0.2 ± 1.2 kg; CG 0.5 ± 1.3 kg) in both groups with no significant group differences. CONCLUSION: In summary, supplementation with 15 g of SCP improved running performance in a 1-h time trial and enhanced indicators of endurance capacity at submaximal exercise intensities such as an increased velocity at the lactate as well as the anaerobic threshold more effectively than CT alone. TRIAL REGISTRATION: ETK: 123/17; DRKS-ID: DRKS00015529 (Registered 07 November 2018-Retrospectively registered); https://drks.de/search/de/trial/DRKS00015529.

Running with whole-body electromyostimulation improves physiological determinants of endurance performance - a randomized control trial.

BACKGROUND: This study aimed to evaluate the physiological and metabolic adaptations to an eight-week running intervention with whole-body electromyostimulation (wbEMS) compared to running without wbEMS. METHODS: In a randomized controlled trial (RCT), 59 healthy participants (32 female/ 27 male, 41 ± 7 years, rel.V̇O2max 40.2 ± 7.4 ml/min/kg) ran twice weekly à 20 min for eight weeks either with a wbEMS suit (EG) or without wbEMS (control group, CG). Before and after the intervention, (i) rel.V̇O2max, heart rate and time to exhaustion were recorded with an incremental step test with an incremental rate of 1.20 km/h every 3 min. They were interpreted at aerobic and (indirect) anaerobic lactate thresholds as well as at maximum performance. (ii) Resting metabolic rate (RQ) as well as (iii) body composition (%fat) were assessed. RESULTS: Following the intervention, V̇O2max was significantly enhanced for both groups (EG ∆13 ± 3%, CG ∆9 ± 3%). Velocity was elevated at lactate thresholds and maximum running speed (EG ∆3 ± 1%, CG ∆2 ± 1%); HRmax was slightly reduced by -1 beat/min. No significant changes were observed for time until exhaustion and lactate. RQ was significantly enhanced following both trainings by + 7%. %fat was reduced for both groups (EG ∆-11 ± 3%, CG ∆-16 ± 5%), without any changes in body mass. Results did not differ significantly between groups. CONCLUSIONS: Both interventions had a positive impact on aerobic power. The rightward shift of the time-velocity graph points towards improved endurance performance. The effects of wbEMS are comparable to those after high-intensity training and might offer a time-efficient alternative to affect physiological and metabolic effects. TRIAL REGISTRATION: German Clinical Trials Register, ID DRKS00026827, date 10/26/21.

Specific collagen peptides increase adaptions of patellar tendon morphology following 14-weeks of high-load resistance training: A randomized-controlled trial.

ABSTRACTThe purpose of this study was to investigate the effect of a supplementation with specific collagen peptides (SCP) combined with resistance training (RT) on changes in structural properties of the patellar tendon. Furthermore, tendon stiffness as well as maximal voluntary knee extension strength and cross-sectional area (CSA) of the rectus femoris muscle were assessed. In a randomized, placebo-controlled study, 50 healthy, moderately active male participants completed a 14-week resistance training program with three weekly sessions (70-85% of 1 repetition maximum [1RM]) for the knee extensors. While the SCP group received 5g of specific collagen peptides daily, the other group received the same amount of a placebo (PLA) supplement. The SCP supplementation led to a significant greater (p < 0.05) increase in patellar tendon CSA compared with the PLA group at 60% and 70% of the patellar tendon length starting from the proximal insertion. Both groups increased tendon stiffness (p < 0.01), muscle CSA (p < 0.05) and muscular strength (p < 0.001) throughout the intervention without significant differences between the groups. The current study shows that in healthy, moderately active men, supplementation of SCP in combination with RT leads to greater increase in patellar tendon CSA than RT alone. Since underlying mechanisms of tendon hypertrophy are currently unknown, further studies should investigate potential mechanisms causing the increased morphology adaptions following SCP supplementation.Trial registration: German Clinical Trials Register identifier: DRKS00029244..

A daily supplementation of 5 g of specific collagen peptides during 14 weeks of high-load resistance training increase patellar tendon hypertrophy compared to the same training regimen and placebo.The resistance training-induced CSA increase, which was most pronounced on proximal and medial patellar tendon sites, is uniformly potentiated along the entire tendon length by supplementation.Patellar tendon stiffness, CSA of the rectus femoris muscle and maximal voluntary knee extension strength increase due to training independently from supplementation.Increased tendon CSA as a result of a stimulating effect of the supplementation with specific collagen peptides on collagen synthesis might be able to decrease tendon stress and support tendon healing.

Effects of a Web-Based Lifestyle Intervention on Weight Loss and Cardiometabolic Risk Factors in Adults With Overweight and Obesity: Randomized Controlled Clinical Trial.

BACKGROUND: The high proportion of people with overweight and obesity has become a worldwide problem in recent decades, mainly due to health consequences, such as cardiovascular diseases, neoplasia, and type 2 diabetes mellitus. Regarding effective countermeasures, the digitization of health services offers numerous potentials, which, however, have not yet been sufficiently evaluated. Web-based health programs are becoming increasingly interactive and can provide individuals with effective long-term weight management support. OBJECTIVE: The purpose of this randomized controlled clinical trial was to evaluate the effectiveness of an interactive web-based weight loss program on anthropometric, cardiometabolic, and behavioral variables and to compare it with a noninteractive web-based weight loss program. METHODS: The randomized controlled trial included people who were aged between 18 and 65 years (mean 48.92, SD 11.17 years) and had a BMI of 27.5 to 34.9 kg/m2 (mean 30.71, SD 2.13 kg/m2). Participants (n=153) were assigned to either (1) an interactive and fully automated web-based health program (intervention) or (2) a noninteractive web-based health program (control). The intervention program focused on dietary energy density and allowed for dietary documentation with appropriate feedback on energy density and nutrients. The control group only received information on weight loss and energy density, but the website did not contain interactive content. Examinations were performed at baseline (t0), at the end of the 12-week intervention (t1), and at 6 months (t2) and 12 months (t3) thereafter. The primary outcome was body weight. The secondary outcomes were cardiometabolic variables as well as dietary and physical activity behaviors. Robust linear mixed models were used to evaluate the primary and secondary outcomes. RESULTS: The intervention group showed significant improvements in anthropometric variables, such as body weight (P=.004), waist circumference (P=.002), and fat mass (P=.02), compared with the control group over the course of the study. The mean weight loss after the 12-month follow-up was 4.18 kg (4.7%) in the intervention group versus 1.29 kg (1.5%) in the control group compared with the initial weight. The results of the nutritional analysis showed that the energy density concept was significantly better implemented in the intervention group. Significant differences in cardiometabolic variables were not detected between the 2 groups. CONCLUSIONS: The interactive web-based health program was effective in reducing body weight and improving body composition in adults with overweight and obesity. However, these improvements were not associated with relevant changes in cardiometabolic variables, although it should be noted that the study population was predominantly metabolically healthy. TRIAL REGISTRATION: German Clinical Trials Register DRKS00020249; https://drks.de/search/en/trial/DRKS00020249. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.3390/ijerph19031393.

Development and validation of a clinical prediction model for return to work after arthroscopic anterior crucial ligament reconstruction.

BACKGROUND: Occupational reintegration after anterior cruciate ligament (ACL) rupture is an important clinical issue including economic and health-related perspectives. This study aims to develop and validate a clinical prediction model of return to work in patients with ACL reconstruction surgery considering evidence-based clinical, anthropometric and occupational factors. METHODS: Data of 562 patients with an ACL rupture receiving an arthroscopic ACL reconstruction were used for analysis. A model for the binary outcome of experiencing an inability to work period of less or more than 14 days (model 1), and a model for finding predictor variables that are linearly associated with a continuous longer inability to work period of over 14 days (model 2) was calculated. Pre-operative determinants including patient characteristics and peri-operative factors were used as predictors for both models. RESULTS: For model 1, the highest increase in odds was observed for the occupational type of work, followed by injury of the medial collateral ligament together with partial weight bearing. Small protective effects were observed for female sex, meniscal suture and work with light occupational strain. The type of occupational work, together with revision surgery, a longer duration of limited range of motion and the presence of cartilage therapy were risk factors for longer inability to work. Discrimination and calibration statistics were satisfactory in internal validation. CONCLUSION: Within the framework of clinical consideration, these prediction models will serve as an estimator for patients, their treating physicians and the socioeconomic partners to forecast the individual cost and benefit of ACL injury.

Can We Make Blood Flow Restriction Training More Accessible? Validity of a Low-Cost Blood Flow Restriction Device to Estimate Arterial Occlusion Pressure.

ABSTRACT: Keller, M, Faude, O, Gollhofer, A, and Centner, C. Can we make blood flow restriction training more accessible? Validity of a low-cost blood flow restriction device to estimate arterial occlusion pressure. J Strength Cond Res 37(8): 1581-1587, 2023-Evidence indicates that low-load resistance training with blood flow restriction (BFR) results in comparable gains in muscle mass and muscle strength as high-load resistance training without BFR. Low-load BFR training is a promising tool for areas such as rehabilitation because individuals are exposed to low mechanical stress. However, BFR training is only safe and effective when the cuff pressure is individually adjusted to the arterial occlusion pressure (AOP). Generally, thresholds for AOP are typically determined with sophisticated laboratory material, including Doppler ultrasound and tourniquet systems. Therefore, this study investigated the validity of a low-cost BFR product with automatic AOP assessment (AirBands International) compared with the gold standard for determining the individual AOP. Valid measurements were obtained at the arms and legs in 104 healthy volunteers. For the arms ( n = 49), a Bland-Altman analysis revealed a mean difference of 7 ± 13 mm Hg between the 2 methods, with slightly higher pressure levels for the gold standard (131 ± 14 mm Hg) than for the low-cost device (125 ± 17 mm Hg). For the legs ( n = 55), the low-cost device reached its maximum pressure capacity in 70% of subjects during AOP identification, making the results on the legs unreliable. Although the low-cost device is a valid tool for identifying the individual AOP in the arms, the device cannot be recommended for use at the legs because of its limited pressure capacity. When using the low-cost device for BFR training at the arms, it is recommended to apply the cuff pressure to 60% of the individual AOP to meet current BFR training guidelines.

Similar patterns of tendon regional hypertrophy after low-load blood flow restriction and high-load resistance training.

PURPOSE: Recent evidence indicates that low-load blood flow restriction (LL-BFR) training elicits an anabolic response in tendinous tissue. The purpose of the present study was to investigate the hypertrophic pattern induced in the Achilles tendon by LL-BFR, in comparison with the regional hypertrophy typically observed with conventional high-load (HL) resistance training. METHODS: N = 40 male participants were randomly and concealed allocated to one of two groups: LL-BFR training (20-35% one-repetition maximum/1RM) or HL training (70-85% 1RM). The training was completed three times per week for a total of 14 weeks. Before and after the training period, Achilles tendon morphology was assessed using magnetic resonance imaging along the entire tendon length. Additionally, dynamic strength measures of the plantar flexors were evaluated. RESULTS: In line with previous findings, dynamic plantar flexion strength was improved to a comparable extent in both groups (LL-BFR: 43.6%; HL: 43.5%). The results also confirmed significant increases in Achilles tendon cross-sectional area with LL-BFR (+5.2%). Moreover, they revealed that the hypertrophic pattern obtained with LL-BFR was similar to regional changes seen with conventional HL training. CONCLUSION: The present findings point towards the notion that despite the low loads being applied, LL-BFR training induces Achilles tendon hypertrophy by potentiating anabolic responses in the same regions as with conventional high-load training. Future studies are needed to (i) focus on the potential mechanisms underlying these tendon morphology changes and (ii) apply and evaluate LL-BFR training in clinical populations to validate these results in rehabilitative settings.

Neuromuscular characteristics of agonists and antagonists during maximal eccentric knee flexion in soccer players with a history of hamstring muscle injuries.

BACKGROUND: Muscle strain injuries (MSIs) in the hamstrings are among the most prevalent injuries in elite soccer. We aimed to examine the relation between biomechanical maladaptation in eccentric strength and neuromuscular factors separated by their time and frequency domains. METHODS: 20 elite soccer players with a previous history of unilateral MSI in the M. biceps femoris (BF) long head and 20 without MSI participated. Knee flexion torques, rate of torque development (RTD) and electromyographic signals (EMG) of the BF, the M. semitendinosus (SMT) and knee extensors were obtained during unilateral maximal eccentric knee flexions performed at slow (30°/s) and fast (120°/s) angular speeds. Root mean squares and mean power frequency (MF) was calculated. RESULTS: In the group with a history of MSI, reduced maximal eccentric flexion torque (slow eccentrics -8±11, p<0.05; fast eccentrics -18±13 N*m, p<0.05) and RTD (-33±28 N*m/s, p<0.05; -95±47 N*m/s, p<0.05) concomitantly occurred with diminished agonistic myoelectrical activities (-4±5% of MVC, p<0.05; -10±7% of MVC, p<0.05) and MFs (-24±13 Hz, p<0.05; -24±18 Hz, p<0.05) in the BF. Simultaneously, antagonistic myoelectric activity was elevated (+4±3% of MVC, p<0.05; +3±3% of MVC, p<0.05) in MSI affected legs as compared to unaffected legs for both eccentric contractions. Deficits in myoelectrical activity (r2 = 0.715, p<0.05; r2 = 0.601, p<0.05) and MF (r2 = 0.484, p<0.05; r2 = 0.622, p<0.05) correlated with deficits in maximal torque in the affected leg in the MSI group. Analysis of SMT demonstrated no significant differences. CONCLUSION: Positive relationships between neuromuscular deficits and the reduced eccentric strength profile underpin neuronal inhibition after MSI. This persistent involvement of dysfunctional synergist and antagonist neural hamstring function in strength weakness is of clinical relevance in sports medicine for prevention and rehabilitation.

Pre-operative knee extensor and flexor torque after secondary ACL rupture: a comparative retrospective analysis.

BACKGROUND: Secondary anterior cruciate ligament (ACL) ruptures are a relevant clinical concern after surgical treatment of a primary ACL rupture. However, there is a lack of scientific evidence related to the role of muscle strength prior to revision surgery in a second ACL rupture. The aim of this study was to assess differences in knee extensor and flexor strength in patients before primary and secondary ACL reconstruction compared to healthy controls. METHODS: In total, n = 69 age, weight and sex matched individuals were included in the study: n = 23 patients with isolated primary ACL rupture, n = 23 with secondary ACL rupture, and n = 23 matched healthy controls. Maximal isokinetic knee extension and flexion torque normalized to body mass was assessed for both legs. RESULTS: For patients with secondary ACL ruptures, torques were reduced in the non-injured (extension: 1.94 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.25 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.70 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.14 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. For patients with a primary ACL rupture torques were reduced in the non-injured (extension: 1.92 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.24 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.38 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.01 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. There were no differences between patients with primary and secondary ruptures, except of the knee extension on the injured leg showing higher values after a secondary ACL rupture (1.38 Nm/kg vs. 1.70 Nm/kg, p < 0.05). CONCLUSIONS: The findings indicate that maximal knee torques were significantly reduced in patients with primary and secondary ACL ruptures before surgical reconstruction for the non-injured and injured leg as compared to healthy controls. Further investigations are needed to assess strength abilities before and after a second revision within a prospective design.

Effects of a 12-Week Web-Based Weight Loss Program for Adults With Overweight and Obesity on COVIDAge and Lifestyle-Related Cardiometabolic Risk Factors: A Randomized Controlled Trial.

The coronavirus disease 2019 (COVID-19) pandemic has induced unhealthy lifestyles, particularly an increase in overweight and obesity, which have been shown to be associated with an increased risk of unfavorable COVID-19 outcomes. Web-based health programs could be a helpful measure, especially in times of severe restrictions. Therefore, the present study aimed to investigate the effects of regular attendance in a 12-week web-based weight loss program on COVIDAge, a new construct for risk assessment of COVID-19, and lifestyle-related cardiometabolic risk factors. N = 92 subjects with overweight and obesity (50.0 ± 10.8 years, 76.1% females, 30.5 ± 2.1 kg/m2) of this randomized controlled trial, which were assigned to an interactive (ONLINE: intervention group) or non-interactive (CON: control group) web-based weight loss program, were included in the data analysis. COVIDAge and cardiometabolic risk factors, including anthropometric outcomes, blood pressure, flow-mediated dilatation, and blood parameters, were assessed before and after the 12-week intervention phase. There was a significant group difference in the change of COVIDAge (ONLINE: -4.2%, CON: -1.3%, p = 0.037). The ONLINE group also showed significantly greater reductions in anthropometric outcomes and systolic blood pressure than the CON group (p < 0.05). To the authors' knowledge, this was the first study investigating the effects of regular attendance in a web-based health program on lifestyle-related risk factors for COVID-19. The results demonstrated that adults with overweight and obesity can improve their COVIDAge and specific cardiometabolic risk factors by using this interactive web-based weight loss program regularly. However, this needs to be confirmed by future studies. This study is registered at the German Clinical Trials Register (DRKS00020249, https://www.drks.de).

Supplementation of Specific Collagen Peptides Following High-Load Resistance Exercise Upregulates Gene Expression in Pathways Involved in Skeletal Muscle Signal Transduction.

Previous evidence suggests that resistance training in combination with specific collagen peptides (CP) improves adaptive responses of the muscular apparatus. Although beneficial effects have been repeatedly demonstrated, the underlying mechanisms are not well understood. Therefore, the primary objective of the present randomized trial was to elucidate differences in gene expression pathways related to skeletal muscle signal transduction following acute high-load resistance exercise with and without CP intake. Recreationally active male participants were equally randomized to high-load leg extension exercise in combination with 15 g CP or placebo (PLA) supplementation. Muscle biopsies from the vastus lateralis muscle were obtained at baseline as well as 1, 4 and 24 h post exercise to investigate gene expression using next generation sequencing analysis. Several important anabolic pathways including PI3K-Akt and MAPK pathways were significantly upregulated at 1 and 4 h post-exercise. Significant between-group differences for both pathways were identified at the 4 h time point demonstrating a more pronounced effect after CP intake. Gene expression related to the mTOR pathway demonstrated a higher visual increase in the CP group compared to PLA by trend, but failed to achieve statistically significant group differences. The current findings revealed a significantly higher upregulation of key anabolic pathways (PI3K-Akt, MAPK) in human skeletal muscle 4 h following an acute resistance training combined with intake of 15 g of specific collagen peptides compared to placebo. Further investigations should examine potential relationships between upregulated gene expression and changes in myofibrillar protein synthesis as well as potential long-term effects on anabolic pathways on the protein level.

Effects of specific collagen peptide supplementation combined with resistance training on Achilles tendon properties.

The purpose of this study was to investigate the effect of specific collagen peptides (SCP) combined with resistance training (RT) on changes in tendinous and muscular properties. In a randomized, placebo-controlled study, 40 healthy male volunteers (age: 26.3 ± 4.0 years) completed a 14 weeks high-load resistance training program. One group received a daily dosage of 5g SCP while the other group received 5g of a placebo (PLA) supplement. Changes in Achilles tendon cross-sectional area (CSA), tendon stiffness, muscular strength, and thickness of the plantar flexors were measured. The SCP supplementation led to a significantly (p = 0.002) greater increase in tendon CSA (+11.0%) compared with the PLA group (+4.7%). Moreover, the statistical analysis revealed a significantly (p = 0.014) greater increase in muscle thickness in the SCP group (+7.3%) compared with the PLA group (+2.7%). Finally, tendon stiffness and muscle strength increased in both groups, with no statistical difference between the groups. In conclusion, the current study shows that the supplementation of specific collagen peptides combined with RT is associated with a greater hypertrophy in tendinous and muscular structures than RT alone in young physically active men. These effects might play a role in reducing tendon stress (i.e., deposition of collagen in load-bearing structures) during daily activities.

Development of a modified cross-over hop test to reduce measurement errors in return-to-competition testing.

CONTEXT: Hop tests play an important role in the rehabilitation process after injuries. A comparison of the jumping distances of both extremities allows for an evaluation of the injured limb. In the conventional cross-over hop test for distance, the jump width (medial vs. lateral) that the athlete has to cross during the jump is not standardised and therefore highly variable. This affects the absolute jump length in each jump series. HYPOTHESIS: Modifying the test may reduce the jump length variance between test series of an athlete as well as the test-dependent variations in the cross-over hop for distance. METHODS: N = 47 athletes from the German and French national Judo youth teams were included in the study (age: 15.3 years ±â€Š13-17). A modified version of the cross-over hop for distance was developed with a cross-over width of 50 cm and a fixed landing zone of 10 cm. The jump lengths of the conventional test and the modified test were documented. The change in jump length variations of the two sexes were compared. RESULTS: The mean value of the coefficient of variation decreased significantly from 4.09 % to 2.83 % (p < 0.01) due to the test modification. This resulted in an absolute improvement in accuracy of 1.26 % and a relative improvement of 30.8 %. A comparison of the limb symmetry index between the conventional and the modified cross-over hop for distance revealed no significant differences. CONCLUSION: The modified cross-over hop for distance showed a significantly lower variation in jump lengths compared with the conventional cross-over hop for distance. As a result, more accurate statements can be made regarding the patient's return-to-competition progress.

Low-Load Blood-Flow Restriction Exercise to Failure and Nonfailure and Myoelectric Activity: A Meta-Analysis.

OBJECTIVE: To compare the short- and long-term effects of low-load resistance training with blood-flow restriction (LL-BFR) versus low- (LL-RT) or high- (HL-RT) load resistance training with free blood flow on myoelectric activity and investigate the differences between failure (exercise performed to volitional failure) and nonfailure (exercise not performed to volitional failure) protocols. DATA SOURCES: We identified sources by searching the MEDLINE, PubMed, CINAHL, Web of Science, CENTRAL, Scopus, SPORTDiscus, and PEDro electronic databases. STUDY SELECTION: We screened the titles and abstracts of 1048 articles using our inclusion criteria. A total of 39 articles were selected for further analysis. DATA EXTRACTION: Two reviewers independently assessed the methodologic quality of each study and extracted the data. A meta-analytic approach was used to compute standardized mean differences (SMDs) ± 95% CIs. Subgroup analyses were conducted for both failure and nonfailure protocols. DATA SYNTHESIS: The search identified 39 articles that met the inclusion criteria. Regarding the short-term effects, LL-BFR increased muscle excitability compared with LL-RT during nonfailure protocols (SMD = 0.61; 95% CI = 0.34, 0.88), whereas HL-RT increased muscle excitability compared with LL-BFR during failure (SMD = -0.61; 95% CI = -1.01, -0.21) and nonfailure (SMD = -1.13; 95% CI = -1.94, -0.33) protocols. Concerning the long-term effects, LL-BFR increased muscle excitability compared with LL-RT during exercises performed to failure (SMD = 1.09; 95% CI = 0.39, 1.79). CONCLUSIONS: Greater short-term muscle excitability levels were observed in LL-BFR than in LL-RT during nonfailure protocols. Conversely, greater muscle excitability was present during HL-RT than LL-BFR, regardless of volitional failure. Furthermore, LL-BFR performed to failure increased muscle excitability in the long term compared with LL-RT.