Strength, rate of force development, power and reactive strength in adult male athletic populations post anterior cruciate ligament reconstruction - a systematic review and meta-analysis

Background Residual deficits in athletic performance are common despite rehabilitation guidelines following anterior cruciate ligament reconstruction including criterion-based progressions to protect healing structures, ensure safe restoration of fundamental physical capacities, and guide appropriate return to sports activities. A synthesis of the available literature is warranted to examine the physical readiness to re-perform of athletic populations in the later stages of rehabilitation in comparison to healthy controls. Objectives To determine the level of strength, power, rate of force development, and reactive strength in adult males who are more than six months following anterior cruciate ligament reconstruction. Methods A systematic review of the literature was undertaken using the Medline, CINAHL and SPORTDiscus databases and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies including males only and assessed strength, power, rate of force development and reactive strength comparing performance to healthy controls were included. A meta-analysis was also performed to compute standardized mean differences (SMD ± 95% confidence intervals), calculated using Hedge’s g, and examine the effect of ACLR on these fundamental physical capacities. Results 2023 articles were identified, of which 14 articles with similar level of evidence and methodological quality met the inclusion criteria. The most commonly investigated and impaired physical capacity was quadriceps (g= -0.89, 95% CI [-1.33,-0.44]) and hamstring strength (g= -0.44, 95% CI [-0.78,-0.10]). Only one study investigated rate of force development and none measuring reactive strength met our eligibility criteria. Conclusions Pooled data showed moderate evidence indicating large and small negative deficits on knee peak extension and flexion, respectively, in male adults at more than 6 months post anteriorcruciate ligament reconstruction. The magnitude of these differences are influenced by graft type and can be mitigated by targeted rehabilitation programs. Insufficient evidence is available in male adults following anterior cruciate ligament reconstruction to examine rate of force development and reactive strength

Relationships between physical capacities and biomechanical variables during movement tasks in athletic populations following anterior cruciate ligament reconstruction

Background Anterior cruciate ligament (ACL) reconstruction has a detrimental impact on athletic performance. Despite rehabilitation guidelines and criterion-based progressions to ensure safe restoration of fundamental physical capacities and maladaptive movement strategies, residual deficits in maximal strength, rate of force development (RFD), power and reactive strength are commonly reported. These combined with associated compensatory inter and intra-limb strategies increase the risk of re-injury. Objective The aim of this article is to examine the relationships between fundamental physical capacities and biomechanical variables during dynamic movement tasks. Design Narrative review Results The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts at who are during the later stages of rehabilitation and RTS Conclusion The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts at who are in the later stages of rehabilitation and RT

The Impact of Coronavirus (COVID-19) Related Public-Health Measures on Training Behaviours of Individuals Previously Participating in Resistance Training: A Cross-Sectional Survey Study

Introduction Understanding the impact of lockdown upon resistance training (RT), and how people adapted their RT behaviours, has implications for strategies to maintain engagement in similar positive health behaviours. Further, doing so will provide a baseline for investigation of the long-term effects of these public health measures upon behaviours and perceptions, and facilitate future follow-up study. Objectives To determine how the onset of coronavirus (COVID-19), and associated ‘lockdown’, affected RT behaviours, in addition to motivation, perceived effectiveness, enjoyment, and intent to continue, in those who regularly performed RT prior to the pandemic. Methods We conducted an observational, cross-sectional study using online surveys in multiple languages (English, Danish, French, German, Italian, Portuguese, Slovakian, Swedish, and Japanese) distributed across social media platforms and through authors’ professional and personal networks. Adults (n = 5389; median age = 31 years [interquartile range (IQR) = 25, 38]), previously engaged in RT prior to lockdown (median prior RT experience = 7 years [IQR = 4, 12]) participated. Outcomes were self-reported RT behaviours including: continuation of RT during lockdown, location of RT, purchase of specific equipment for RT, method of training, full-body or split routine, types of training, repetition ranges, exercise number, set volumes (per exercise and muscle group), weekly frequency of training, perception of effort, whether training was planned/recorded, time of day, and training goals. Secondary outcomes included motivation, perceived effectiveness, enjoyment, and intent to continue RT. Results A majority of individuals (82.8%) maintained participation in RT during-lockdown. Marginal probabilities from generalised linear models and generalised estimating equations for RT behaviours were largely similar from pre- to during-lockdown. There was reduced probability of training in privately owned gyms (~ 59% to ~ 7%) and increased probability of training at home (~ 18% to ~ 89%); greater probability of training using a full-body routine (~ 38% to ~ 51%); reduced probability of resistance machines (~ 66% to ~ 13%) and free weight use (~ 96% to ~ 81%), and increased probability of bodyweight training (~ 62% to ~ 82%); reduced probability of moderate repetition ranges (~ 62–82% to ~ 55–66%) and greater probability of higher repetition ranges (~ 27% to ~ 49%); and moderate reduction in the perception of effort experienced during-training (r = 0.31). Further, individuals were slightly less likely to plan or record training during lockdown and many changed their training goals. Additionally, perceived effectiveness, enjoyment, and likelihood of continuing current training were all lower during-lockdown. Conclusions Those engaged in RT prior to lockdown these behaviours with only slight adaptations in both location and types of training performed. However, people employed less effort, had lower motivation, and perceived training as less effective and enjoyable, reporting their likelihood of continuing current training was similar or lower than pre-lockdown. These results have implications for strategies to maintain engagement in positive health behaviours such as RT during-restrictive pandemic-related public health measures

The benefits of strength training on musculoskeletal system health: practical applications for interdisciplinary care

Global health organizations have provided recommendations regarding exercise for the general population. Strength training has been included in several position statements due to its multi-systemic benefits. In this narrative review, we examine the available literature, first explaining how specific mechanical loading is converted into positive cellular responses. Secondly, benefits related to specific musculoskeletal tissues are discussed, with practical applications and training programmes clearly outlined for both common musculoskeletal disorders and primary prevention strategies

Optical and Morphological Studies of Thermally Evaporated PTCDI-C8 Thin Films for Organic Solar Cell Applications

PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient) have been extracted from the spectroscopic ellipsometry (SE). X-ray reflectivity (XRR) and atomic force microscopy (AFM) were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization

Low load resistance training with blood flow restriction decreases anterior knee pain more than resistance training alone. A pilot randomised controlled trial

Objectives: To evaluate if application of blood flow restriction (BFR) combined with low-load resistance training (LLRT) would induce significant anterior knee pain (AKP) reduction compared to LLRT alone. Design: Randomised Controlled Trial. Setting: Institutional physiotherapy clinic. Participants: Forty males suffering from AKP were randomly allocated in the LLRT-BFR or LLRT group. BFR was applied at 80% of complete vascular occlusion. Four sets of open kinetic chain knee extensions were implemented in both groups using a pain monitoring model. Main outcome measures: Pain (0–10) was assessed immediately after LLRT-BFR or LLRT application and after a physiotherapy session (45 min) during shallow and deep single-leg squat (SLSS, SLSD), and step-down test (SDT). Results: Significant immediate pain reduction was found in LLRT-BFR group in SLSS, SLSD and SDT (d = 1.32, d = 1.12, d = 0.88 respectively), but no difference was found in LLRT group. Following the physiotherapy session pain reduction was sustained in LLRT-BFR group in both SLSs and SDT (d = 1.32, d = 0.78, d = 0.89 respectively). For the control group significant pain reduction was only found in SLSS (d = 0.56). No significant between-group differences were observed. Conclusions: The pain reduction induced by LLRT-BFR could indicate this intervention as a preconditioning process prior to the rehabilitation of AKP. © 2018 Elsevier Lt

Cross-cultural adaptation of the VISA-P questionnaire for Greek-speaking patients with patellar tendinopathy

Objectives To cross-culturally adapt the VISA-P questionnaire for Greek-speaking patients and evaluate its psychometric properties. Background The VISA-P was developed in the English language to evaluate patients with patellar tendinopathy. The validity and use of self-administered questionnaires in different language and cultural populations require a specific procedure in order to maintain their content validity. Methods The VISA-P questionnaire was translated and cross-culturally adapted according to specific guidelines. The validity and reliability were tested in 61 healthy recreational athletes, 64 athletes at risk from different sports, 32 patellar tendinopathy patients and 30 patients with other knee injuries. Participants completed the questionnaire at baseline and after 15-17 days. Results The questionnaire's face and content validity were judged as good by the expert committee, and the participants. Concurrent validity was almost perfect (rho=-0.839, p< 0.001). Also, factorial validity testing revealed a two-factor solution, which explained 85.6% of the total variance. A one-factor solution explained 80.8% of the variance when the other knee injury group was excluded. Known group validity was demonstrated by significant differences between patients compared with the asymptomatic groups (p< 0.001). The VISA-PGR exhibited very good test-retest reliability (ICC=0.818, p< 0.001; 95% CI 0.758 to 0.864) and internal consistency since Cronbach's a analysis ranged from alpha=0.785 to 0.784 following a 15-17 days interval. Conclusions The translated VISA-P-GR is a valid and reliable questionnaire and its psychometric properties are comparable with the original and adapted versions

No differences in spinal repositioning error in patients with low back pain presenting with a directional preference into extension

Aim: To compare repositioning error, habitual and self-perceived optimal sitting posture, between patients with low back pain presenting with a directional preference into extension and asymptomatic individuals. Method: Fifteen patients with low back pain were matched with 15 asymptomatic individuals. Lumbo-pelvic repositioning error, pain, functional disability, and depression were evaluated. Participants reproduced two target positions (neutral and lordotic sitting postures) after slump sitting. Results: No significant differences (all p >.05) were detected between patients with low back pain and asymptomatic individuals in error direction, magnitude and variability. Furthermore, no differences were found in habitual or self-perceived optimal posture between the patients and control groups. Conclusions: We found no evidence of deficits in proprioception in patients with mild low back pain and directional preference into extension. While the lack of clear deficits in repositioning error is consistent with many previous studies, there are also data suggesting deficits in repositioning error among patients with low back pain. Variations in methodology, the population of patients studied, and especially their level of pain, could explain this variation. The lack of consistent deficits in repositioning error suggests other factors, across the biopsychosocial spectrum, may be more relevant in the development, and persistence, of low back pain. © 2019 Informa UK Limited, trading as Taylor & Francis Group

Repeated end range spinal movement while seated abolishes the proprioceptive deficit induced by prolonged flexed sitting posture. A study assessing the statistical and clinical significance of spinal position sense

Background Sustained spinal flexion has been proposed to affect the properties of spinal tissues, increase postural muscle's activation latency and act detrimentally on proprioception. Objectives This study evaluated the effect of flexed posture (FP) on spinal proprioception and assessed the immediate effect of spinal movement on the presumable flexion-induced proprioceptive deficit. Design Clinical measurement study. Methods Marker-based kinematic analyses of the head, spine, and pelvis were conducted on 50 individuals. Subjects were educated in a lordotic sitting posture (IOSP) that they reproduced immediately; after 10 and 30 min in FP; and after sagittal spinal movement. Nine sagittal angles were calculated. Absolute error (AE) and constant error (CE) were used to evaluate repositioning accuracy. Repeated measures ANOVA was used to test for significant differences in angles obtained among postures, as well as for the AE and CE calculated from the trials. Results No significant differences were found in reposition error (RE) after immediate reproduction of IOSP (all p > 0.0083). Following FP AEs presented significant differences for head (4.1°), head protraction (1.9°), head tilt (2.1°), lumbar (3.2°) and pelvis angle (2.1°). CEs revealed significant differences for head protraction (−1.8°) and lumbar angle (−3.5°). No significant differences were found for AE and CE after spinal sagittal movement (all p > 0.0083). Conclusions Prolonged FP can affect spinal position sense, but sagittal spinal movement can abolish the proprioceptive deficit. The significant differences documented, may be of limited clinical utility given their magnitude, and the reliability data presented may be of use in reinterpreting previously documented proprioceptive analyses. © 2017 Elsevier Lt