Quadriceps Strength Research Articles

Evaluating the Efficacy of Kinesthesia, Balance, and Vestibulo-Postural Training in Knee Osteoarthritis Management

Background: Knee osteoarthritis (OA) is a common degenerative joint disease that causes pain, reduced mobility, and impaired quality of life. This study compares the efficacy of kinesthesia and balance exercises with isometric strengthening versus vestibulo-postural training using a bipodalic stabilometric platform with isometric strengthening in improving muscle strength and functional independence in knee OA patients. Methods: Thirty subjects with knee OA, aged between 30-60 years, were randomly assigned to two groups. Group 1 (n=15) received kinesthesia and balance exercises along with isometric strengthening exercises, while Group 2 (n=15) received vestibulo-postural training using a bipodalic stabilometric platform combined with isometric strengthening exercises. Both groups performed their respective exercise regimens three times a week for four weeks. Outcomes measured included quadriceps and hamstrings strength using the Manual Muscle Testing (MMT) grading system and functional independence using the Barthel Index score. Results: Group 2 demonstrated significantly greater improvements in quadriceps strength (mean change: 1.34 vs. 0.40; p < 0.001), hamstrings strength (mean change: 1.07 vs. 0.20; p < 0.001), and Barthel Index score (mean change: 20.54 vs. 5.5; p < 0.001) compared to Group 1. The between-group analysis confirmed that vestibulo-postural training with isometric strengthening was significantly more effective in enhancing muscle strength and functional independence in knee OA patients. Conclusion: Vestibulo-postural training using a bipodalic stabilometric platform combined with isometric strengthening exercises significantly improves muscle strength and functional independence in knee OA patients compared to kinesthesia and balance exercises with isometric strengthening. These findings highlight the importance of incorporating dynamic and challenging balance exercises into OA management strategies to optimize patient outcomes and enhance quality of life..

Effect of Sampling Rate, Filtering, and Torque Onset Detection on Quadriceps Rate of Torque Development and Torque Steadiness.

Quadriceps rate of torque development (RTD) and torque steadiness are valuable metrics for assessing explosive strength and the ability to control force over a sustained period of time, which can inform clinical assessments of knee function. Despite their widespread use, there is a significant gap in standardized methodology for measuring these metrics, which limits their utility in comparing outcomes across different studies and populations. To address these gaps, we evaluated the influence of sampling rates, signal filtering, and torque onset detection on RTD and torque steadiness. Twenty-seven participants with a history of a primary anterior cruciate ligament reconstruction (N = 27 (11 male/16 female), age = 23 ± 8 years, body mass index = 26 ± 4 kg/m2) and thirty-two control participants (N = 32 (13 male/19 female), age = 23 ± 7 years, body mass index = 23 ± 3 kg/m2) underwent isometric quadriceps strength testing, with data collected at 2222 Hz on an isokinetic dynamometer. The torque-time signal was downsampled to approximately 100 and 1000 Hz and processed using a low-pass, zero-lag Butterworth filter with a range of cutoff frequencies spanning 10-200 Hz. The thresholds used to detect torque onset were defined as 0.1 Nm, 1 Nm, and 5 Nm. RTD between 0 and 100 ms, 0 and 200 ms, and 40-160 ms was computed, as well as absolute and relative torque steadiness. Relative differences were computed by comparing all outcomes to the "gold standard" values computed, with a sampling rate of 2222 Hz, a cutoff frequency in the low-pass filter of 150 Hz, and torque onset of 1 Nm, and compared utilizing linear mixed models. While all combinations of signal collection and processing parameters reached statistical significance (p < 0.05), these differences were consistent between injured and control limbs. Additionally, clinically relevant differences (+/-10%) were primarily observed through torque onset detection methods and primarily affected RTD between 0 and 100 ms. Although measurements of RTD and torque steadiness were generally robust against diverse signal collection and processing parameters, the selection of torque onset should be carefully considered, especially in early RTD assessments that have shorter time epochs.

Impact du genre sur les effets de la réadaptation respiratoire chez les patients atteints de BPCO

Introduction: COPD has become more prevalent among women, revealing a specific feminine phenotype. Women experience greater dyspnea and a more impaired quality of life.The main objective of this study was to assess the effect of gender on dyspnea during a pulmonary rehabilitation program (PRP).Methods: Retrospective study including COPD patients having participated in PRPs. The following data were analyzed according to gender before and after a PRP: dyspnea, quality of life, anxiety and depression, exercise capacity, muscle function (quadriceps and inspiratory muscles).Results: More than 500 patients (252 men and 252 women) were included. We did not find a significant effect of gender on the evolution of dyspnea, anxiety or depressive disorders, exercise capacity, inspiratory muscle strength, or overall quality of life score. That said, we found a possible effect on the sub-scores of the quality-of-life questionnaire, and regarding quadriceps strength. All criteria improved during the program in both groups.Conclusions: During a PRP, gender does not impact the evolution of dyspnea. While women may nonetheless benefit to a greater extent in terms of quality of life sub-scores (impact, activities, symptoms) and quadriceps strength, these results still require confirmation.

Sleep restriction reduces voluntary isometric quadriceps strength through reduced neuromuscular efficiency, not impaired contractile performance.

To determine how SR affects quadriceps contractile function and recruitment. Eighteen healthy subjects (9M, 9F, age 23.8 ± 2.8y) underwent isometric (maximal and submaximal), isokinetic (300-60°·s-1), and interpolated twitch (ITT) assessment of knee extensors following 3d of adequate sleep (SA; 7-9h·night-1), 3d of SR (5h·night-1), and 7d of washout (WO; 7-9h·night-1). Compared to SA (227.9 ± 76.6Nm) and WO (228.19 ± 62.9Nm), MVIC was lesser following SR (209.9 ± 73.9Nm; p = 0.006) and this effect was greater for males (-9.8 v. -4.8%). There was no significant effect of sleep or sleep x speed interaction on peak isokinetic torque. Peak twitch torque was greater in the potentiated state, but no significant effect of sleep was noted. Males displayed greater potentiation of peak twitch torque (12 v. 7.5%) and rate of torque development (16.7 v. 8.2%) than females but this was not affected by sleep condition. ITT-assessed voluntary activation did not vary among sleep conditions (SA: 81.8 ± 13.1% v. SR: 84.4 ± 12.6% v. WO 84.9 ± 12.6%; p = 0.093). SR induced a leftward shift in Torque-EMG relationship at high torque output in both sexes. Compared to SA, females displayed greater y-intercept and lesser slope with SR and WO and males displayed lesser y-intercept and greater slope with SR and WO. Three nights of SR decreases voluntary isometric knee extensor strength, but not twitch contractile properties. Sex-specific differences in neuromuscular efficiency may explain the greater MVIC reduction in males following SR.

To Compare the Effects of 0.2% Ropivacaine Continuous Infusion versus Programmed Intermittent Bolus on Postoperative Analgesia with Adductor Canal Block, in Patients Undergoing Unilateral Knee Arthroplasty: A Randomized Controlled Trial

Background: Multimodal regimens are the mainstay of postoperative analgesia. Analgesic effectiveness of programmed intermittent bolus (PIB) versus continuous infusion (CI) in ultrasound-guided adductor canal block (ACB) for unilateral knee arthroplasty, were compared. Materials and Methods: Following Ethical and Clinical Trials Registry approval, eligible patients were administered pericapsular infiltration, intraoperatively and ACB with catheter, postoperatively. As per randomization, the PIB group received 10 ml 0.2% ropivacaine every 3 hourly while the CI group received 6mL/h. In addition, both groups received patient controlled boluses of 5mL with lockout interval of 30 minutes. The numerical rating score (NRS) score, plasma concentration of ropivacaine, use of rescue analgesics, quadricep strength by Straight Leg Rising Test (SLRT), Medical Research Council (MRC) scale for motor power, were monitored at 0, 1, 4, 24, 48 h, and Likert Scale for patient satisfaction, was measured at 72 h. To be clinically meaningful, sample size calculation, was according to a difference in NRS, for a power of 0.80, and σ‐standard deviation of two points, thus requiring at least 17 patients in each group. Results: In PIB group, patients experienced better analgesia in the first 24 h (rest - 95% CI - 0.089–0.669, P = 0.010 and movement - 95% CI - 0.82–0.884, P = 0.018) and motor power, in the first (P = 0.051) and 4th h (P = 0.034), after recovery, along with improved patient satisfaction (P = 0.001). Ropivacaine plasma concentration, at regular intervals, was independent of the pain scores with rest and movement. Rescue analgesia was inconclusive in both groups. Conclusion: The PIB option provided better analgesia in the postoperative period.

DYNamic Assessment of Multi-Organ level dysfunction in patients recovering from COVID-19: DYNAMO COVID-19.

We evaluated the impacts of COVID-19 on multi-organ and metabolic function in patients following severe hospitalised infection compared to controls. Patients (n=21) without previous diabetes, cardiovascular or cerebrovascular disease were recruited 5-7months post-discharge alongside controls (n=10) with similar age, sex and body mass. Perceived fatigue was estimated (Fatigue Severity Scale) and the following were conducted: oral glucose tolerance (OGTT) alongside whole-body fuel oxidation, validated magnetic resonance imaging and spectroscopy during resting and supine controlled exercise, dual-energy X-ray absorptiometry, short physical performance battery (SPPB), intra-muscular electromyography, quadriceps strength and fatigability, and daily step-count. There was a greater insulin response (incremental area under the curve, median (inter-quartile range)) during the OGTT in patients [18,289 (12,497-27,448) mIU/min/L] versus controls [8655 (7948-11,040) mIU/min/L], P<0.001. Blood glucose response and fasting and post-prandial fuel oxidation rates were not different. This greater insulin resistance was not explained by differences in systemic inflammation or whole-body/regional adiposity, but step-count (P=0.07) and SPPB scores (P=0.004) were lower in patients. Liver volume was 28% greater in patients than controls, and fat fraction adjusted liver T1, a measure of inflammation, was raised in patients. Patients displayed greater perceived fatigue scores, though leg muscle volume, strength, force-loss, motor unit properties and post-exercise muscle phosphocreatine resynthesis were comparable. Further, cardiac and cerebral architecture and function (at rest and on exercise) were not different. In this cross-sectional study, individuals without known previous morbidity who survived severe COVID-19 exhibited greater insulin resistance, pointing to a need for physical function intervention in recovery.

Effect of exercise on postoperative recovery of patients with non-small cell lung cancer: a systematic review and meta-analysis

Patients with non-small cell lung cancer (NSCLC) in the postoperative recovery period often experience reduced exercise capacity and impaired lung function, which affects their overall quality of life. This paper investigated the effect of exercise interventions on exercise capacity, lung function, quality of life, and symptoms in these patients. Methods: We performed a literature search across Cochrane, Embase, PubMed, Web of Science, and EBSCO databases were comprehensively searched for randomized controlled trials (RCTs) from inception to September 2023, all English RCTs were eligible if they assessed the effects of exercise interventions on postoperative NSCLC patients. Results: Twelve articles met our inclusion criteria, evidencing that exercise interventions could significantly improve the functional capacity of NSCLC patients in postoperative recovery. Notably, Forced Expiratory Volume in 1 s (FEV1) was improved, indicating enhanced lung function. Furthermore, exercise improved the physical and mental health scores of SF-36, along with increased quadriceps strength and relieved dyspnea. However, fatigue levels were not significantly changed. Conclusions: Exercise interventions of NSCLC patients in the postoperative recovery are associated with improved functional capacity, lung function, quality of life, and quadriceps strength, as well as alleviated symptoms of dyspnea. These findings underscore the potential benefits of incorporating exercise into postoperative care for NSCLC patients. Nonetheless, further large-scale RCTs are required to solidify the evidence base on the clinical outcomes of exercise following pneumonectomy.

Effects of Gluteal Muscles Isometrics on Abdominals, Back Extensors and Quadriceps Strength

Background: Weakness of the gluteus muscle is associated with multiple types of injuries such as low back, hip and knee pathology. However, there is no research regarding the effect of gluteal isometric exercises on abdominals, back extensors and quadriceps muscles strength. Hence, this study aimed to demonstrate the effect of gluteal isometric exercises on abdominals, back extensors and quadriceps strength. Methods: A total of 100 healthy students aged between 18 and 25 years were recruited to participate in an 8-week program of gluteal muscle isometric exercises. The strength of the abdominal, back extensor, and quadriceps muscles was assessed both at baseline and after the 8-week intervention period. Results: A paired sample t-test revealed significant improvements in abdominal muscles, back extensor muscle strength (p&lt;0.001), and quadriceps muscle strength (p=0.037) after an 8-week intervention. The greatest increases were observed in the abdominals (59.05%), back extensors (46.78%), and quadriceps (7.13%). Conclusion: This study demonstrates that gluteal isometric exercises had a significant positive effect on the strength of abdominals, back extensors and quadriceps muscles.

MES-FES Interface Enhances Quadriceps Muscle Response in Sitting Position in Incomplete Spinal Cord Injury: Pilot Study

Purpose: In incomplete spinal cord injury (SCI), there is a partial decrease in motor or sensory or autonomic function. Mainly due to the motor impairment in SCI, a muscle–machine interface is a tool that can bring functional benefits to this population. Objective: To investigate the feasibility of the non-invasive myoelectric signal–functional electrical stimulation (MES-FES) interface on the response of the quadriceps muscle in an individual with incomplete SCI. Methods: This is a quasi-experimental, uncontrolled, longitudinal case report study carried out with an individual with incomplete SCI in the chronic phase. The assessments performed before (pre) and after eight (post8) interventions were neuromuscular assessment (surface electromyography (EMG) in rectus femoris (RF) and vastus lateralis (VL) muscles); muscle strength (load cell); knee extension range of motion (goniometry); spasticity (Modified Ashworth Scale); and quality of life (Spinal Cord Injury Quality-of-Life Questionnaire (SCI-QoL.Br)). The MES-FES interface was associated with physical therapy exercises on the extension knee joint muscle group. Results: Improvement in neuromuscular activation (normalized increase in EMGRMS of 2% (RF) and 3.3% (VL)) and synchronism of the motor units (normalized reduction in EMGMDF of 22.8% (RF) and 5.9% (VL)); 1.4 kgf increase in quadriceps strength; 10.6° increase in knee joint extension amplitude; 1 point spasticity reduction; improved quality of life, confirmed by a 12-point reduction in the SCI-QoL.Br score. Moreover, along with interventions, the participant increased the correct FES activation rate, indicating a user learning curve (ρ = 0.78, p-value = 0.04). Conclusions: The MES-FES interface associated with physical therapy promotes neuromuscular and quality of life improvements in the SCI participant.

Reliability and Validity of Temporal Parameters during the Side Hop Test in Patients after Anterior Cruciate Ligament Reconstruction.

Background: The side hop test (SHT) measures the number of jumps performed over 30 s. Although this measure has demonstrated its value in clinical practice, the temporal parameters of the SHT allow for a deeper analysis of the execution strategy. The aim of this study is to assess the reliability and construct validity of contact time parameters during the SHT recorded by a video analysis system in anterior cruciate ligament reconstructed (ACLR) patients. Methods: We investigated the reliability (intra-rater, standard error of measurement (SEM), and minimum detectable change (MDC)), discriminant validity (operated (OP) versus non-operated (NOP) side), and convergent validity (relationship with strength and psychological readiness) of SHT contact time parameters, number of valid hops and limb symmetry index (LSI) in 38 ACLR patients. Contact time parameters are presented as mean, standard deviation (SD), and coefficient of variation (CV) of contact time. Results: Intra-tester reliability was good to excellent for all contact time parameters. For discriminant validity, the mean and SD contact times of the OP leg were significantly longer than those of the NOP leg, although the difference was smaller than the SEM and MDC values. The number of valid jumps and CV contact time parameters were not significantly different. Isokinetic quadriceps strength (60°/s) was strongly correlated with mean contact time for both legs. However, psychological readiness was not correlated with any of the contact time parameters. Conclusions: Temporal parameters of the SHT measured on video analysis are valid and reliable parameters to assess the performance strategy of the SHT. The results should be interpreted with caution regarding the SEM and MDC values. Further studies are needed to measure criterion validity, inter-rater reliability, and responsiveness.

Long-term Assessment of Functional Outcomes and Quality of Life in Patients Undergoing Total Knee Arthroplasty.

While short-term outcomes of total knee arthroplasty (TKA) have been extensively studied, there is a need for longstanding assessments to understand the enduring impact of the procedure on patient well-being. A retrospective cohort research to rate the longstanding functional outcomes and quality of life (QoL) in those undergoing primary TKA. Patient-reported outcomes, including SF-36 and EQ-5D scores, were collected at multiple time points postoperatively (1, 5, and 10 years). Objective assessments of functional parameters, i.e., range of motion, gait analysis, and quadriceps strength, were also recorded. Current findings demonstrate significant improvements in functional outcomes post-TKA, with sustained benefits observed over a 10-year period. Range of motion, gait parameters, and quadriceps strength showed consistent enhancements postoperatively. Moreover, QoL measures, as reflected by SF-36 and EQ-5D scores, exhibited substantial improvements following TKA and remained elevated throughout the follow-up period. This research highlights the enduring effectiveness of TKA in improving both functional outcomes and QoL in patients with advanced knee arthritis.

The impact of various massage gun percussive therapy protocols on physiological adaptations

Current protocols for delivering percussive therapy (PT) using massage guns are heterogenetic creating a need to establish the impact of study design on physiological measures and the standardisation of future research. This study aimed to determine the most effective protocol on lower body strength, net impulse, and flexibility, and to support the provision of protocol validation for future research. With institutional ethics approval, a convenience sample of recreationally active healthy adults (n = 35; a-priori calculation suggested 34 participants) with no lower body massage gun PT experience, undertook two main protocols; three sessions per week at 2100 rpm or increasing the speed for each session: 1750 to 2100 to 2400 rpm. PT was applied at tolerable pressure for 60 s to each of the quadriceps, gluteals, hamstrings and calves of both legs. Paired-samples t tests (alpha levels: P = .05) assessed pre- and post-intervention data for strength, net impulse, and flexibility. These were collected in all sessions using a dynamometer, My Jump 2 app and goniometer allowing changes for eight different protocols to be reported with Cohen’s d. After three sessions a week involving increments in speed, results showed significant improvements in strength (dominant; non-dominant) of quadriceps (P = .005, d = 0.51; P &lt; .001, d = 0.77), hamstrings (P = .001, d = 0.61; P = .006, d = 0.49) and calves (P &lt;.001, d = 0.69; P = .015, d = 0.44), and flexibility of hamstrings (P &lt; .001, d = 1.14; P &lt; .001, d = 0.74) and calves (P = .04, d = 0.36; P = .005, d = 0.51). Combined lower body muscle strength (quadriceps, hamstrings and calves) increased on average by 10.1% (mean ± 2.14 kg, range ± 1.30-2.98 kg) and flexibility (hamstrings and calves) increased on average by 5.8% (mean ± 1.77°, range ± 1.70-5.66°). A significant improvement (P = 0.33, d = 0.36) was seen in net impulse after three treatments a week at 2100rpm, an increase of 3.2% (mean ± 4.75 N·s). The most effective protocol for gains in lower body strength and flexibility is applying massage gun PT three times a week with increased speeds across sessions (1750, 2100, 2400rpm). For gains in net impulse, the most effective protocol is three applications a week at 2100 rpm. Practitioners using these protocols could target specific improvements in physiological adaptations and in addition, and in addition researchers may wish to adopt these protocols to allow homogenous analysis across study populations in future research.

Eccentric Muscle Strengthening Using Maximal Contractions Is Deleterious in Knee Osteoarthritis: A Randomized Clinical Trial.

Objectives: To show the superiority of eccentric versus concentric strengthening in terms of improving quadriceps strength in knee osteoarthritis (OA), a randomized controlled study was conducted to perform 12 sessions of either eccentric or concentric isokinetic muscle strengthening over 6 weeks. Methods: We recruited males and females, aged between 40 and 70 years, with predominantly unilateral femorotibial OA. Exclusion criteria were having a prosthesis, inflammatory arthritis or flare-up of OA, symptomatic patellofemoral OA, cardiovascular or pulmonary disease that could be a contraindication to the study treatment, and any pathology that could cause muscle weakness. The primary endpoint was the between-group difference in change in maximum concentric isokinetic knee extension peak torque (PT) at 60°/s on the OA side at 6 weeks. Secondary endpoints were between-group difference in change in concentric hamstring PT at 60°/s; eccentric quadriceps and hamstring PT at 30°/s; 10 m and 200 m walking speeds; pain and functional status (WOMAC score) at 6 weeks and 6 months. Results: The sample consisted of 11 females and 27 males, with a mean age of 57.7 ± 7.52 years and a body mass index (BMI) of 25.95 ± 3.93 kg/m2. Quadriceps strength increased more at 6 weeks in the concentric than the eccentric group with no statistical difference. There was a rate of 25% major adverse events in the eccentric group. Conclusions: Eccentric training resulted in a smaller improvement in quadriceps strength than concentric training and was associated with a high risk of muscle injury, particularly to the hamstring muscles.

Effect of open vs. closed kinetic chain exercises in ACL rehabilitation on knee joint pain, laxity, extensor muscles strength, and function: a systematic review with meta-analysis.

PROSPERO [CRD42023475230].

Comparison of Analgesic Effects of Continuous Femoral Nerve Block, Femoral Triangle Block, and Adductor Block After Total Knee Arthroplasty: A Randomized Clinical Trial.

This study aimed to compare the analgesic effects of continuous femoral nerve block (FNB), femoral triangle block (FTB), and adductor canal block (ACB) following total knee arthroplasty (TKA). The goal was to identify the most effective nerve block technique among these. Patients undergoing TKA were randomly assigned to 1 of 3 groups: FNB, FTB, or ACB. Nerve blocks were administered preoperatively, with catheters placed for patient-controlled nerve analgesia (PCNA). The primary end point was the Numeric Rating Scale (NRS) score at movement at 24 hours postsurgery. Secondary end points included NRS scores at rest and movement, quadriceps strength, Timed Up and Go (TUG) test performance, range of motion, effective PCNA utilization, and opioid consumption at various postsurgery time points. Of the 94 valid data sets analyzed (FNB: 31, FTB: 31, ACB: 32), significant differences were observed in the primary end point (H=7.003, P =0.03). Post hoc analysis with Bonferroni correction showed that the FNB group had a significantly lower median pain score (3 [2 to 4]) compared with the ACB group (4 [3 to 5], Bonferroni-adjusted P =0.03). Regarding secondary end points, both the FNB and FTB groups had significantly lower NRS scores than the ACB group at various time points after surgery. Quadriceps strength and TUG completion were better in the FTB and ACB groups. There were no statistically significant differences among the groups for the other end points. Continuous FTB provides postoperative analgesia comparable to FNB but with the advantage of significantly less impact on quadriceps muscle strength, a benefit not seen with FNB. Both FTB and ACB are effective in preserving quadriceps strength postoperatively.

Knee Extensor Torque Steadiness and Quadriceps Activation Variability in Collegiate Athletes 4, 6, and 12 Months After ACL Reconstruction.

Quadriceps performance after anterior cruciate ligament reconstruction (ACLR) is typically characterized by peak force/torque, but the ability to generate consistent knee extensor torque may be clinically meaningful. The purpose of this study was to evaluate knee extensor torque steadiness and quadriceps activation variability in collegiate athletes 4 to 12 months after ACLR. It was hypothesized that between-limb asymmetries in torque steadiness and activation variability would be observed and that steadiness would be associated with activation variability and peak knee extensor torque symmetry. Case-control study; Level of evidence, 3. A total of 30 National Collegiate Athletic Association Division I athletes completed maximal voluntary isometric contractions 4, 6, and 12 months after ACLR. Torque and surface electromyography of the superficial quadriceps were recorded. Torque steadiness was calculated as the mean difference between initial and low-pass filtered torque signals and was expressed as a percentage of peak torque. Quadriceps activation variability was calculated similarly and was expressed as a percentage of peak electromyography. Linear mixed models were used to assess change in torque steadiness and activation variability over time. Associations between torque steadiness of the operated limb, activation variability, and quadriceps strength symmetry were evaluated using the Spearman correlation coefficient. Limb-by-time interactions were detected for torque steadiness and activation variability (P < .001), with reductions (improvements) in limb steadiness and activation variability observed with increasing time since surgery. Between-limb differences in torque steadiness and activation variability were observed at 4 and 6 months postoperatively (P < .05). Significant associations between operated limb torque steadiness and quadriceps activation variability were observed at 4 months (P < .001) and 6 months (P < .01). Torque steadiness of the operated limb was associated with peak knee extensor torque symmetry at 4 months (r S = -0.49; P < .01) and 6 months (r S = -0.49; P < .01). In collegiate athletes, impaired knee extensor torque steadiness of the operated limb and associated abnormal quadriceps activation patterns were observed 4 to 12 months after ACLR, and the consistency of knee extensor torque production was associated with greater quadriceps strength asymmetries, particularly 4 to 6 months after surgery. Operated limb torque steadiness and activation variability improved from 4 to 12 months after ACLR. Clinical assessment of knee extensor torque steadiness after ACLR may improve prognosis and specificity of rehabilitation efforts.

Beyond weakness: Exploring intramuscular fat and quadriceps atrophy in ACLR recovery.

Muscle weakness following anterior cruciate ligament reconstruction (ACLR) increases the risk of posttraumatic osteoarthritis (OA). However, focusing solely on muscle weakness overlooks other aspects like muscle composition, which could hinder strength recovery. Intramuscular fat is a non-contractile element linked to joint degeneration in idiopathic OA, but its role post-ACLR has not been thoroughly investigated. To bridge this gap, we aimed to characterize quadriceps volume and intramuscular fat in participants with ACLR (male/female = 15/9, age = 22.8 ± 3.6 years, body mass index [BMI] = 23.2 ± 1.9, time since surgery = 3.3 ± 0.9 years) and in controls (male/female = 14/10, age = 22.0 ± 3.1 years, BMI = 23.3 ± 2.6) while also exploring the associations between intramuscular fat and muscle volume with isometric strength. Linear mixed effects models assessed (I) muscle volume, (II) intramuscular fat, and (III) strength between limbs (ACLR vs. contralateral vs. control). Regression analyses were run to determine if intramuscular fat or volume were associated with quadriceps strength. The ACLR limb was 8%-11% smaller than the contralateral limb (p < 0.05). No between-limb differences in intramuscular fat were observed (p = 0.091-0.997). Muscle volume but not intramuscular fat was associated with strength in the ACLR and control limbs (p < 0.001-0.002). We demonstrate that intramuscular fat does not appear to be an additional source of quadriceps dysfunction following ACLR and that muscle size only explains some of the variance in muscle strength.

Blood Flow Restriction Therapy After Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament reconstruction (ACLR) rehabilitation necessitates restoration of quadriceps strength to minimize reinjury and optimize return to sport (RTS). Patients recovering from ACLR are limited by pain and activity restrictions, resulting in quadriceps muscle atrophy. Blood flow restriction (BFR) therapy involves performing exercises while a specialized blood pressure cuff is applied to the proximal aspect of the operative extremity and inflated to 40% to 90% of the arterial occlusion pressure, as determined using Doppler ultrasonography. BFR is theorized to induce an anaerobic environment and metabolic stress during exercise, promoting muscle hypertrophy and strength gains. Although the physiological mechanism has not been fully elucidated, it is theorized that BFR combined with low-load resistance training could yield muscle adaptations comparable to those of high-load resistance training. For ACLR patients with pain and restrictions precluding high-intensity strength training, incorporation of BFR into postoperative rehabilitation protocols could help mitigate quadriceps weakness and promote RTS. Randomized controlled trials report a prolonged, dose-dependent relation between BFR use and quadriceps and hamstring strength gains, improved bone and muscle mass, and earlier RTS, whereas other studies report no significant difference in quadriceps size, strength, or patient satisfaction compared with controls. Furthermore, although generally considered safe, there are rare reports of associated adverse events such as rhabdomyolysis, and BFR should be avoided in patients with a history of thromboembolic disease or peripheral vasculopathy. The literature examining BFR after ACLR is heterogeneous; lacks standardization; and contains broad variation in reported cuff pressures, as well as timing and duration of BFR use, among protocols. Although the use of BFR after ACLR shows promise, further study is necessary to elucidate the efficacy, safety, and optimal protocols.

Blood Flow Restriction Enhances Recovery After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Randomized Controlled Trials

To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating neuromuscular and clinical outcomes of blood flow restriction (BFR) training after anterior cruciate ligament reconstruction (ACLR) compared with non-BFR rehabilitation protocols. A systematic review was performed in accordance with the 2020 Preferred Reporting Items for Systematic reviews and Meta Analyses guidelines by querying PubMed, MEDLINE, Scopus, the Cochrane Database for Systematic Review, and the Cochrane Central Register for Controlled Trials databases from inception through December 2023 to identify Level I and II RCTs evaluating outcomes of BFR training after ACLR compared with non-BFR rehabilitation. A meta-analysis was performed using random-effects models with standardized mean difference (SMD) for pain, muscle strength, and muscle volume, whereas mean difference was calculated for patient-reported outcome measures. Eight RCTs, consisting of 245 patients, met inclusion criteria, with 115 patients undergoing non-BFR rehabilitation compared with 130 patients undergoing BFR after ACLR. Mean patient age was 27.2 ± 6.7 years, with most patients being male (63.3%, n= 138/218). The length of the BFR rehabilitation protocol was most commonly between 8 and 12 weeks (range, 14 days to 16 weeks). Most studies set the limb/arterial occlusion pressure in the BFR group at 80%. When compared with non-BFR rehabilitation, BFR resulted in significant improvement in isokinetic muscle strength (SMD: 0.77, P= .02, I2: 58%), International Knee Documentation Committee score (mean difference: 10.97, P ≤ .00001, I2: 77%), and pain (SMD: 1.52, P= .04, I2: 87%), but not quadriceps muscle volume (SMD: 0.28, P= .43, I2: 76%). The use of BFR after ACLR led to improvements in pain, International Knee Documentation Committee score, and isokinetic muscle strength, with variable outcomes on the basis of quadriceps strength, volume, and thickness when compared with non-BFR rehabilitation. Level II, systematic review and meta-analysis of Level I and II studies.

Assessment of muscle dysfunction in COPD patients: A case-control study

Introduction: peripheral muscle dysfunction satellite of chronic obstructive pulmonary disease (COPD) has emerged in recent years as a major factor which limits patients' ability to exercise. Methods: This study is a case-control investigation of the associations between COPD and muscle dysfunction. Cases and control subjects were recruited to evaluate their body composition using bioelectrical impedance (BIA). Quadriceps strength and endurance tests were performed. Dyspnoea was estimated by the mMRC scale. The patients were redirected from the department of pulmonary diseases of Batna, Algeria. The healthy subjects were volunteers without any lung, heart or systemic diseases or handicap in physical effort. Results: 175 patients with stable COPD (9 female and 166 male) aged between 40–86 years, mean FEV1 52 ± 21% and 175 age-and-sex-matched healthy subjects (FEV1: 91± 9%) were included in this study. The cigarette consumption was 35 (20) pack/years in COPD patients vs 15 (15) pack/years in healthy subjects. The classification of airflow limitation showed that 19.43% of patients were classified GOLD I, 30.29% (GOLD II), 33.71% (GOLD III), and 16.57% (GOLD IV). 22. 85% of COPD patients were classified in (category A) ,17.14% (category B) ,16.57% (category C) and 43.42% (category D). fat-free mass index (FFMI) was 19.3 (1.6) kg/m2 in COPD patients vs 18 (4.7) kg/m2 in controls. Quadriceps strength was 109.27 (42.8) Nm in COPD patients vs 141.6 (15) Nm in healthy subjects. The quadriceps endurance was 3.75 (1.14) min in patients vs 16.6 (15) min in controls. Conclusion: This study supports the idea that skeletal muscle mass, quadriceps strength and endurance, were adversely affected in patients with COPD.