The Importance of Functional Hamstring/Quadriceps Ratios in Knee Osteoarthritis

Muscle activation patterns and gait changes in unilateral knee osteoarthritis patients: a comparative study with healthy controls

The objective of this study was to investigate the differences in muscle activation and kinematic parameters between patients with unilateral knee osteoarthritis (OA) and healthy individuals. Additionally, the study aimed to determine the correlation between muscle activation and kinematic parameters with knee OA symptoms. Participants with unilateral knee OA (n = 32) and healthy individuals (n = 32) completed the gait test. Electromyography (EMG) and motion capture were employed to collect muscle activation data and kinematic parameters. Spearman's correlation coefficient was used to analysis the correlation between BMI, symptomatic side EMG parameters, kinematic parameters, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. Furthermore, a multiple linear regression analysis of WOMAC pain was also conducted. The peak root mean square, integrated electromyography, and co-activation index (CCI) were increased bilaterally in the unilateral knee OA group compared to the healthy group. Furthermore, these values were higher on the symptomatic side than on the asymptomatic side. Compared with the healthy group, the knee OA group had lower gait speed, decreased stride length and cadence on bilateral sides, longer total stance time and double-stance time, and shorter single stance time and swing time. The maximum knee flexion angle of the swing phase on the symptomatic side of the knee OA group was smaller than that on the asymptomatic side and healthy group. Changes in EMG and gait parameters on the symptomatic side correlated with WOMAC scores. The main factors influencing WOMAC pain were the CCI values of the lateral femoral and biceps femoris muscles and gait speed. Muscle activation and kinematic parameters in the lower limbs of patients with unilateral knee OA were altered bilaterally during walking. These alterations on the symptomatic side were associated with knee OA-related pain. ChiCTR2200064958. Date of registration: 2022-10-24. Key Points • Unilateral symptomatic knee OA leads to bilateral alterations in muscle activation and gait parameters. • Symptomatic muscle activation and gait parameter changes in knee OA patients are associated with knee OA symptoms. • Correcting abnormal muscle activation conditions and gait training may reduce knee OA-related pain.

There is more to the knee joint than just the quadriceps: A systematic review with meta-analysis and evidence gap map of hamstring strength, flexibility, and morphology in individuals with gradual-onset knee disorders

BACKGROUND

Impairments in hamstring strength, flexibility, and morphology have been associated with altered knee biomechanics, pain, and function. Determining the presence of these impairments in individuals with gradual-onset knee disorders is important and may indicate targets for assessment and rehabilitation. This systematic review aimed to synthesize the literature to determine the presence of impairments in hamstring strength, flexibility, and morphology in individuals with gradual-onset knee disorders.

METHODS

Five databases (MEDLINE, Embase, CINAHL, SPORTDiscus, and Web of Science) were searched from inception to September 2022. Only studies comparing hamstring outcomes (e.g., strength, flexibility, and/or morphology) between individuals with gradual-onset knee disorders and their unaffected limbs or pain-free controls were included. Meta-analyses for each knee disorder were performed. Outcome-level certainty was assessed using the Grading of Recommendations Assessment, Development, and Evaluation, and evidence gap maps were created.

RESULTS

Seventy-nine studies across 4 different gradual-onset knee disorders (i.e., knee osteoarthritis (OA), patellofemoral pain (PFP), chondromalacia patellae, and patellar tendinopathy) were included. Individuals with knee OA presented with reduced hamstring strength compared to pain-free controls during isometric (standard mean difference (SMD) = -0.76, 95% confidence interval (95%CI) : -1.32 to -0.21) and concentric contractions (SMD = -0.97, 95%CI : -1.49 to -0.45). Individuals with PFP presented with reduced hamstring strength compared to pain-free controls during isometric (SMD = -0.48, 95%CI : -0.82 to -0.14), concentric (SMD = -1.07, 95%CI : -2.08 to -0.06), and eccentric contractions (SMD = -0.59, 95%CI : -0.97 to -0.21). No differences were observed in individuals with patellar tendinopathy. Individuals with PFP presented with reduced hamstring flexibility when compared to pain-free controls (SMD = -0.76, 95%CI : -1.15 to -0.36). Evidence gap maps identified insufficient evidence for chondromalacia patellae and hamstring morphology across all gradual-onset knee disorders.

CONCLUSION

Our findings suggest that assessing and targeting impairments in hamstring strength and flexibility during rehabilitation may be recommended for individuals with knee OA or PFP.

Analysis of lower limb muscle strength characteristics of amateur runners with patellofemoral pain: A cross-sectional study

To analyze the lower limb muscle strength characteristics of amateur runners with patellofemoral pain (PFP). Sixty amateur runners (30 in the knee pain group, 30 in the control group) underwent measurements of hip abduction strength, knee extension strength, and knee flexion strength. Additionally, the hamstring/quadriceps ratio and limb strength symmetry index were calculated for all participants. Statistical analyses were conducted using linear mixed models. The hip abduction and knee extensors strength of amateur runners with PFP was significantly lower than that of the control group. The hamstring/quadriceps ratio was significantly higher in the male knee pain group compared to the control group, while no significant difference was found between the female knee pain group and the control group. Furthermore, both the hip abduction strength symmetry index and knee extensors symmetry index were significantly lower in the knee pain group compared to the control group. Amateur runners with PFP exhibit distinct lower limb strength characteristics compared to non-knee pain runners. Additionally, differences in lower limb strength characteristics between male and female amateur runners with PFP were observed. These findings emphasize the importance of considering functional and gender differences in PFP rehabilitation training.

Comparison of the asymmetries in muscle mass, biomechanical property and muscle activation asymmetry of quadriceps femoris between patients with unilateral and bilateral knee osteoarthritis

Background: More and more attention has been paid to the research of muscle mass and muscle quality of quadriceps femoris (QF) in knee osteoarthritis (KOA). This study aimed to explore the asymmetric changes of muscle mass, biomechanical property and muscle activation in the inter-limbs QF of KOA patients, and tried to provide a novel insight for the evaluation, prevention and treatment of KOA. Methods: A total of 56 Participants with unilateral or bilateral KOA were included in this study: 30 patients with unilateral pain and 26 patients with bilateral pain were assigned to the bilateral group (BG) and unilateral group (UG), respectively. The symptom severity of bilateral lower limbs was evaluated by visual analogue scale, and the relatively serious leg (RSL) and relatively moderate leg (RML) were classified. The thickness of rectus femoris (RF), vastus intermedius (VI), vastus medialis (VM) and vastus lateralis (VL) were measured by ultrasound. The Shear wave elastography (SWE) techniqie was used to measure the shear modulus of RF, VM and VL. Surface electromyography (sEMG) was used to assess the root mean square (RMS) of the RF, VM, and VL during straight leg raising in a sitting position and squatting task. We calculated the asymmetry indexes of inter-limbs for the corresponding indices of the measured muscles. Result: Thickness of RF, VI and VL of RSL was lower than those on RML (p < 0.05), and thickness of VM was lower more significant (p < 0.01). Thickness of RF, VI and VL of RSL was also lower than those of RML in BG (p < 0.05), however, there was no significant difference in VM thickness (p > 0.05). There were no significant difference in Asymmetry indexes of all measured muscle thickness between the two groups (p > 0.05). The Shear modulus of RF, VM, and VL in the RML of UG and BG was higher than those in the RSL (p < 0.05). In sitting and straight leg raising task, the RMS of RF, VM and VL in RML were higher than those in RSL, UG and BG both showed this trend (p < 0.05). About squatting task, in UG, the RMS of the three muscles in RML of patients were also higher than those in the RSL (p < 0.05). However, the difference was not significant in BG (p > 0.05). In the straight leg raising task, the asymmetry indexes of RMS in RF, VM, and VL of both the two groups were positively correlated with VAS scores (p < 0.05). Conclusion: The muscle thickness, shear modulus and muscle activation electromyography of QF in RML were higher than those of RSL in unilateral KOA patients. The VM of RML in bilateral KOA patients may show muscle thickness degeneration earlier, which is closer to the VM of RSL. The shear modulus of RF, VM, and VL were higher on the RML side during the single-leg task, but there may be passive compensation for muscle activation in both lower limbs during the bipedal task. In conclusion, there is a general asymmetry of QF muscle mass, biomechanics Characteristic and performance in patients with KOA, which may provide new ideas for the assessment, treatment and rehabilitation of the disease.

Effects of Self-management Program as Adjunctive to Usual Rehabilitation Exercise on Pain and Functional Outcomes in Knee Osteoarthritis: A Randomized Controlled Trial

BACKGROUND

Home-based exercise (HBE) and patient education (EDU) have been reported as beneficial additions to usual knee osteoarthritis (KOA) rehabilitation. However, previous trials mostly examined the effects of HBE and EDU separately. Thus, this study aimed to evaluate the effects of a structured combined HBE and EDU program in addition to usual KOA rehabilitation on pain score, functional mobility, and disability level.

STUDY DESIGN

A parallel-group, single-blinded randomized controlled trial.

METHODS

Eighty adults with KOA were randomly allocated to experimental (n=40) and control (n=40) groups. All participants underwent their usual physiotherapy care weekly for eight weeks. The experimental group received a structured HBE+EDU program to their usual care, while the control group performed home stretching exercises to equate treatment time. The Knee Injury and Osteoarthritis Outcome Score (KOOS) for the disability level, visual analogue scale (VAS) for pain, and timed up-and-go test (TUG) for mobility were measured pre-post intervention.

RESULTS

After eight weeks, the experimental group demonstrated significant improvements in the KOOS (all subscales), pain VAS, and TUG scores compared to baseline (P<0.001); meanwhile, only KOOS (activities of daily living and sports subscales) was significant in the control group. Relative to the control, the experimental group presented higher improvements (P<0.001) by 22.2%, 44.1%, and 15.7% for KOOS, pain VAS, and TUG, respectively.

CONCLUSION

Integrating the HBE+EDU program into usual KOA rehabilitation could reduce pain and disability, while it improved functional mobility. The finding of this study suggests a combination of a structured HBE and EDU program to be considered as part of mainstream KOA management.

Epidemiology of High Intensity Functional Training (HIFT) injuries in Brazil

BACKGROUND

High intensity functional training (HIFT), usually called CrossFit, is a physical training that has gained much popularity in the past few years. The risk of acute and overuse injuries in HIFT is unclear. This study evaluated the incidence of injuries in HIFT, characterizing severity, location, and associated risk factors.

METHODS

This cross-sectional study was conducted between January and May 2021. HIFT practitioners were recruited through social media and answered an online questionnaire on training characteristics and injury history.

RESULTS

A total of 606 subjects (264 male and 342 female) were included. The average age of the participants was 29.78 ± 7.14 years. The mean height was 169.60 ± 8.96 cm, and the mean body mass was 73.69 ± 13.11 kg. Overall, participants were involved in HIFT for an average of 25.36 ± 20.29 months. A total of 58.6% of participants took part in 5 to 6 training sessions per week, 31.7% practiced 5 to 6 h per week. 62.7% of the responders performed other physical activities in parallel, 98.2% performed warm-up before the training, and a formal cooldown was accomplished by 29.4% of participants. 6.8% of athletes followed individual worksheets. 45.9% of participants participated in competition.

CONCLUSIONS

The overall rate of injuries was 3.51/1000 h. 59.2% of subjects experienced two or more injuries. The shoulder was involved in 21.3% of cases, lower back in 18.3%, and the knee in 13.4%. No difference was found in injury rate between males and females. Experienced athletes were more prone to injury compared to those who trained under 12 months. Approximately the half of injuries did not cause training interruption. No difference was found in injury rate between males and females. The purpose of the participant did not impact the injury rate, nor did the practice of warm-up and cooldown, the time of weekly training, the league and level of competition. Finally, the participation in other sports in parallel did not demonstrated association with the injury occurrence.

TRIAL REGISTRATION

The present study was approved by the Ethics and Research Committee by Plataforma Brazil and follows the Resolution 466/2012/CNS/MS/CONEP.

Isokinetic strengthening and neuromuscular electrical stimulation protocol impact on physical performances, functional status and quality of life in knee osteoarthritis overweight/obese women

BACKGROUND

Knee muscle weakness associated with overweight/obesity can lead to impairment of vital daily function in knee osteoarthritis patients. This study investigated the effect of a knee eccentric isokinetic muscle strength (IMS) training program combined with neuromuscular electrical stimulation (NMES) on muscle strength and flexibility, joint ROM, functional status, physical performance, and quality of life in knee osteoarthritis overweight/obese women.

METHODS

Thirty-six women were randomized into three groups, two experimental groups (EG) and a control group following a classic rehabilitation program. During 6 weeks of two sessions/week, one of the two EGs performed an IMS program (ISO.G); the other underwent combined IMS and NMES training (ISO + NMES.G). All patients were evaluated with clinical examination, isokinetic test at 60°/s and 240°/s speeds, physical performance tests related to activities of daily living, and Knee injury and Osteoarthritis Outcome Score (KOOS) quality of life questionnaire, before and after the intervention.

RESULTS

In the 10-m walk, chair stand, stair climb and monopodal stance tests, muscle flexibility and quality of life scores showed significant improvement for ISO.G (P = 0.000) and ISO + NMES.G (P = 0.000). Concentric strength at 240°/s was improved in ISO + NMES.G (P = 0.000) unlike the muscle strength at 60°/s (quadriceps, P = 0.104; hamstrings, P = 0.171), force asymmetry (P = 0.481) and post-intervention joint ROM (P = 0.309).

CONCLUSIONS

The combination of IMS and NMES shows significant superiority over the usual rehabilitation program for the majority of the parameters measured for optimal management of knee osteoarthritis.

Gastrocnemius Muscle Injury Is the Condition to Induce Cartilage Degeneration of the Rabbit Tibiofemoral Joint: A New Perspective

The knee osteoarthritis is a common joint disease that causes pain and inconvenience. Clinically, patients with knee osteoarthritis often have response points on the gastrocnemius. Gastrocnemius plays an essential role in stabilizing joints and changing gait and pace, which also has a close relationship with the knee joint. The objective of this study is to determine changes in the tibiofemoral joint after medial and lateral gastrocnemius injury. Rabbits were divided into a medial gastrocnemius injury group, a lateral gastrocnemius injury group, and a control group with two intervals: 6 and 8 weeks after modeling of the semisevered gastrocnemius. The gastrocnemius was weighed and sectioned for histology. The joint space and subchondral bone were observed using X-ray and microcomputed tomography. The cartilage was observed histologically using Safranin O fast green and Masson and immunohistochemically using antibodies to collagen type II, matrix metalloproteinase 13, and integrin beta1. Results showed muscle fiber atrophy, and fibrotic changes occurred after gastrocnemius semidissociation. After gastrocnemius injury, the femoral condyle of the tibiofemoral joint produced abnormal sclerosis and bone degeneration. The pathological changes of cartilage included disordered or reduced cell alignment, cartilage matrix loss, and collagen loss due to decreased collagen type II and increased matrix metalloproteinase 13 activity. The increase of integrin beta1 in the injured group may be related to mechanical conduction process. The results suggest that gastrocnemius injury is an essential factor in tibiofemoral arthritis.

Temporal differences in the myoelectric activity of lower limb muscles during rearfoot and forefoot running: A statistical parametric mapping approach

The aim of this study was to apply statistical parametric mapping (SPM) to compare temporal changes in EMG amplitude between rearfoot (RF) and forefoot (FF) running techniques. Eleven recreational runners ran on a treadmill at a self-selected speed, once using a RF strike pattern and once using a FF strike pattern (randomized order). The myoelectric activity of five lower limb muscles [rectus femoris (RFe), biceps femoris (BF), tibialis anterior (TA), medial and lateral gastrocnemius (MG and LG)] was evaluated, using bipolar electromyography (EMG). EMG data from the RF and FF running techniques was then processed and posteriorly compared with SPM, dividing the analysis of the running cycle into stance and swing phases. The MG and LG muscles showed higher activation during FF running at the beginning of the stance phase and at the end of the swing phase. During the end of the swing phase the TA muscle's EMG amplitude was higher, when the RF running technique was used. A higher level of co-activation between the gastrocnemius and TA muscles was observed at the end of the swing phase during RF running. The myoelectric behaviour of the RFe and BF muscles was similar during both running techniques. These findings highlight the importance of SPM for the accurate assessment of differences in muscle activity during running and strongly suggest that these two running techniques predominately reflect adjustments of the leg and not the thigh muscles.