Heightened Flexor Withdrawal Responses in Subjects With Knee Osteoarthritis

Patients with osteoarthritic (OA) knee pain often present with impaired muscle activation and function that may be attributed in part to hyperexcitability of flexion withdrawal reflexes (FWRs). The aim of this study was to investigate alterations in the excitability of FWR in individuals with knee OA and its potential associations with impaired quadriceps activation (QA) and subjective reports of pain. Twenty subjects with and 20 without knee OA (age, 45 to 75 years) participated. Impaired QA was determined in OA subjects during maximal volitional contraction of the quadriceps. FWRs were tested in isometric conditions using electrocutaneous stimulation applied at the medial foot at 1× and 2× FWR threshold and surface electromyographic recordings obtained from tibialis anterior (TA) and biceps femoris (BF). Joint torques at the hip, knee, and ankle were calculated and normalized to body mass. FWR threshold was significantly diminished in OA versus the control group (P < .01). In addition, FWR latencies were consistent with spinally mediated responses, with significantly earlier responses in OA versus control subjects of TA at threshold (P = .002) and BF at suprathreshold stimulation (P = .0006). Impaired QA was found in 4 of 20 OA subjects but was not correlated to FWR threshold or pain levels. Peak joint torques were diminished in the OA versus the control group (P < .0006).PerspectiveIncreased excitability of FWRs was evident in subjects with chronic knee osteoarthritis, including those subjects without resting pain, but was not associated with impaired QA. Management strategies for this patient population must consider altered pain processing in addition to addressing impairments found at the knee.     

Assessment of Movement-Evoked Pain in Osteoarthritis by the Knee-Bend and CatWalk Tests: A Clinically Relevant Study

Although there are several reports on pain behavioral tests in rat models of knee osteoarthritis (OA), most of them focus on the paw. The aim of this study was to investigate pain-related behaviors on the affected knee joint, the primary source of nociception, in animals with mono-iodoacetate–induced OA, using the knee-bend (which provides information on movement pain) and pin-prick tests, and to evaluate nociception elicited by walking using the CatWalk test. The von Frey and Randall-Selitto tests applied to the paw allowed us to compare our study results with previous studies. A further aim was to compare the behavioral nociceptive responses of the most used doses of mono-iodoacetate, 2 and 3 mg. Knee-bend score of OA animals was higher than those of control animals throughout the study (P < .05). At every time point, the ipsilateral hind-paw load of OA rats, as measured by the CatWalk test, was lower than that of control rats (P < .05), and paw withdraw threshold to von Frey filaments was also decreased (P < .01). No changes were observed in pin-prick and Randall-Selitto tests. Results obtained with the 2 doses of mono-iodoacetate were similar. The knee-bend and CatWalk tests are effective for evaluating movement-related nociception, a hallmark of clinical OA, which was present throughout the experimental period.PerspectiveBehavioral characterization of models of OA pain is important and useful for use in future studies to test pharmacological treatments. Furthermore, it is important to find methods that correlate better with the human symptoms of OA.     

Immediate Efficacy of Laterally Wedged Insoles With Arch Support on Walking in Persons With Bilateral Medial Knee Osteoarthritis

ObjectiveTo investigate the immediate efficacy of laterally wedged insoles with arch support (LWAS) on gait in persons with bilateral medial knee osteoarthritis (OA).DesignA prospective case-control intervention study.SettingA gait laboratory with a 6-camera motion analysis system and 2 forceplates.ParticipantsFifteen women with bilateral medial knee OA and 15 healthy control subjects (N=30).InterventionsLWAS.Main Outcome MeasuresSubjective knee pain and objective biomechanical indices, namely, joint angles and moments in the frontal plane, frontal plane ground reaction force and lever arm, as well as medial/lateral center of mass and center of pressure during gait.ResultsWhen wearing the LWAS, knee pain during gait in persons with medial knee OA decreased (P=.01). Peak internal knee abductor moments were also reduced (P<.001) with increasing foot progression angles, laterally shifted center of pressure, and a shortened frontal plane lever arm (all P<.05). However, ankle invertor moments were increased (P<.05) when wearing the LWAS.ConclusionsAlthough peak internal knee abductor moment and knee pain were immediately reduced during gait when wearing the LWAS, increased ankle invertor moments were found, suggesting that the LWAS should be used with caution. Strengthening and monitoring the condition of the ankle invertor muscles may be necessary if the LWAS is used as an intervention for persons with bilateral medial knee OA.     

Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Alters Emotional Modulation of Spinal Nociception

Emotion has a strong modulatory effect on pain perception and spinal nociception. Pleasure inhibits pain and nociception, whereas displeasure facilitates pain and nociception. Dysregulation of this system has been implicated in development and maintenance of chronic pain. The current study sought to examine whether emotional modulation of pain could be altered through the use of transcranial direct current stimulation (tDCS) to enhance (via anodal stimulation) or depress (via cathodal stimulation) cortical excitability in the dorsolateral prefrontal cortex. Thirty-two participants (15 female, 17 male) received anodal, cathodal, and sham tDCS on three separate occasions, followed immediately by testing to examine the impact of pleasant and unpleasant images on pain and nociceptive flexion reflex (NFR) responses to electrocutaneous stimulation. Results indicated that tDCS modulated the effect of image content on NFR, F(2, 2175.06) = 3.20, P= .04, with the expected linear slope following anodal stimulation (ie, pleasant < neutral < unpleasant) but not cathodal stimulation. These findings provide novel evidence that the dorsolateral prefrontal cortex is critical to emotional modulation of spinal nociception. Moreover, the results suggest a physiological basis for a previously identified phenotype associated with risk for chronic pain and thus a potentially new target for chronic pain prevention efforts.PerspectiveThis study demonstrated that reduction of dorsolateral prefrontal cortical excitability by transcranial direct current stimulation attenuates the impact of emotional image viewing on nociceptive reflex activity during painful electrocutaneous stimulation. This result confirms there is cortical involvement in emotional modulation of spinal nociception and opens avenues for future clinical research.     

Joint mobilization reduces hyperalgesia associated with chronic muscle and joint inflammation in rats.

Joint mobilization is a common treatment used by healthcare professions for management of a variety of painful conditions, including inflammatory joint and muscle pain. We hypothesized that joint mobilization would reduce the bilateral hyperalgesia induced by muscle and joint inflammation. Mechanical hyperalgesia was measured by examining the mechanical withdrawal threshold of the rat's paw before and after induction of inflammation with 3% carrageenan (gastrocnemius muscle) or 3% kaolin/carrageenan (knee joint), and for 1 hour after knee joint mobilization. The mobilization consisted of rhythmically flexing and extending the knee joint to the end of range of extension while the tibia was simultaneously moved in an anterior to posterior direction. A bilateral decrease in mechanical withdrawal thresholds occurred 1, 2, and 4 weeks after inflammation of the knee joint or muscle. In animals with muscle inflammation, mobilization of the knee joint increased the mechanical withdrawal threshold bilaterally when given 1, 2, or 4 weeks after inflammation. However, in animals with knee joint inflammation, mobilization of the knee joint at 4 weeks increased the mechanical withdrawal threshold but had no effect when administered 1 or 2 weeks after inflammation. Therefore, joint mobilization reduces hyperalgesia induced by chronic inflammation of muscle and joint. PERSPECTIVE: This article shows that unilateral joint mobilization reduces bilateral hyperalgesia induced by chronic muscle or joint inflammation. Understanding the pain conditions in which mobilization produces an analgesic effect should assist the clinician in selecting appropriate treatment techniques. The bilateral effect suggests that central mechanisms could mediate the analgesia.     

Preoperative Neuropathic Pain-like Symptoms and Central Pain Mechanisms in Knee Osteoarthritis Predicts Poor Outcome 6 Months After Total Knee Replacement Surgery

Preoperative pain characteristics in patients with osteoarthritis may explain persistent pain after total knee replacement. Fifty patients awaiting total knee replacement and 22 asymptomatic controls were recruited to evaluate the degree of neuropathic pain symptoms and pain sensitization. Patients with OA were pain phenotyped into 2 groups based on the PainDETECT questionnaire: high PainDETECT group (scores ≥19) indicating neuropathic pain-like symptoms and low PainDETECT group (scores <19) indicating nociceptive or mixed pain. Cuff algometry assessing pain detection thresholds and pain tolerance thresholds was conducted on the lower legs. Temporal summation of pain was assessed using 10 sequential cuff stimulations and a von Frey stimulator. Conditioning pain modulation was assessed by cuff pain conditioning on 1 leg and parallel assessment of pain detection thresholds on the contralateral leg. Pressure pain thresholds were recorded by pressure handheld algometry local and distant to the knee. Knee pain intensity (visual analogue scale) and pain assessments were collected before and 6 months after total knee replacement. Thirty percent of patients demonstrated neuropathic pain-like symptoms (high PainDETECT group). Facilitated temporal summation of pain and reduced pressure pain thresholds distant to the knee were found in the high PainDETECT group compared with the low PainDETECT group and healthy controls (P < .001). Patients with OA with high PainDETECT scores had higher postoperative visual analogue scale pain scores than the low PainDETECT patients (P < .0001) and facilitated temporal summation of pain (P = .022) compared with healthy control subjects.Perspective: This study has found that preoperative PainDETECT scores independently predict postoperative pain. Patients with knee OA with neuropathic pain-like symptoms identified using the PainDETECT questionnaire are most at risk of developing chronic postoperative pain after TKR surgery.     

Joint Mobilization of the Hands of Patients With Rheumatoid Arthritis: Results From an Assessor-Blinded,Randomized Crossover Trial

ObjectiveThe purpose of this study was to assess the clinical feasibility and effectiveness of manual mobilization of the hands of patients with rheumatoid arthritis (RA).MethodsA total of 320 individual hand joints were evaluated after recruiting an experimental research group of 12 participants with RA and, for clinical comparability, 8 participants with hand osteoarthritis (OA). One hand per participant was randomized to receive weekly low-grade (I-II) Kaltenborn manual mobilization, using passive sustained stretch of the metacarpophalangeal (MCP) joints II to V by licensed manual therapists. After 2 weeks, the randomized treated hand was crossed over to control (untreated) during weeks 3 to 4 and vice versa. Final assessment was at 2 months, which was 1 month after the last treatment at week 4. Primary hand outcomes included pain by visual analog scale, tender or swollen joint count, and presence of Doppler signal or synovial fluid and radiographic joint space by musculoskeletal ultrasound.ResultsIn the RA group, both the initially randomized treated hand and the contralateral hand improved significantly from baseline to crossover to follow-up at 2 months (pain outcomes and Doppler signal, P < .050; synovial fluid and MCP joint space, P ≤ .001). Hand pain and MCP joint space also improved significantly in OA. There were no dropouts or reported adverse events in either the RA or OA group.ConclusionIn this study, manual mobilization of the hands of patients with RA was shown to be feasible, safe, and effective to integrate into specialized healthcare.     

Joint Distraction Magnitude Is Associated With Different Behavioral Outcomes and Substance P Levels for Cervical Facet Joint Loading in the Rat

The facet joint is a common source of pain in both the neck and low back, and can be injured by abnormal loading of the spinal joints. Whereas a host of nociceptive changes including neuronal activation, neuropeptide expression, and inflammatory mediator responses has been reported for rat models of joint pain, no such responses have been explicitly investigated or quantified for painful mechanical injury to the facet joint. Two magnitudes of joint loading were separately imposed in a rat model of cervical facet joint distraction: Painful and nonpainful distractions. Behavioral outcomes were defined by assessing mechanical hyperalgesia in the shoulders and forepaws. Substance P (SP) mRNA and protein levels were quantified in the dorsal root ganglion (DRG) and spinal cord at days 1 and 7 following distraction. Painful distraction produced mechanical hyperalgesia that was significantly greater (P < .010) than that for a nonpainful distraction. Painful distraction significantly increased spinal SP mRNA (P = .048) and SP protein expression in the DRG (P = .013) at day 7 compared to nonpainful distraction. However, spinal SP protein for painful distraction was significantly less (P = .024) than that for nonpainful distraction at day 1. Joint distractions producing different behavioral outcomes modulate SP mRNA and protein in the DRG and spinal cord, suggesting that SP responses may be involved with different temporal responses in painful joint loading.PerspectiveSP mRNA and protein in the DRG and spinal cord are quantified at 2 time points after cervical facet joint distractions that separately do or do not produce mechanical hyperalgesia. Studies describe a role for SP to contribute to pain produced by mechanical joint loading.     

Possible startle response contamination of the spinal nociceptive withdrawal reflex.

The objective of this study was to examine the possibility that the spinal nociceptive withdrawal reflex, otherwise known as the RIII reflex, is contaminated by the startle response, which is a non-pain-related supraspinal response. Startle response contamination of the RIII reflex would seriously compromise the RIIIs ability to measure spinal nociceptive processes in man, since a change in the startle response affecting EMG amplitude in the RIII latency range would be erroneously interpreted as a change in a spinal nociceptive process. EMG responses evoked by electrical stimulation of the sural nerve were recorded from the orbicularis oculi, neck, biceps, and biceps femoris muscles in 31 healthy human volunteers. The startle response was elicited under conditions often used to record the RIII reflex. Procedures are described that will completely eliminate the startle response. Comparisons between subjects that did and did not elicit a startle response revealed that the startle does not appear to significantly contaminate the biceps femoris RIII reflex, at least when performing group comparisons. There are, however, situations not dealt with in this study in which the startle might significantly contaminate the RIII reflex, such as patients with pre-existing negative emotional states, experimental procedures that induce fear and/or anxiety, and single case studies. It is important, therefore, that investigators using the RIII reflex be cognizant of the startle response and take appropriate precautions to monitor and if necessary eliminate the startle before attributing a change in the RIII reflex to a spinal nociceptive process.     

自我效能干预在创伤后膝关节活动受限中的应用

目的:观察自我效能干预对于创伤后膝关节活动受限的影响.方法:将符合纳入标准的创伤后膝关节活动受限患者99例,随机分为对照组49例和观察组50例,2组均接受常规综合康复治疗,包括肌力训练、关节松动术、物理因子治疗、中医治疗和牵伸技术,观察组在常规治疗基础上给予自我效能干预.2组治疗前和治疗4周后采用膝关节ROM,视觉模拟...     

Concurrent neuromechanical and functional gains following upper-extremity power training post-stroke

Background

Repetitive task practice is argued to drive neural plasticity following stroke. However, current evidence reveals that hemiparetic weakness impairs the capacity to perform, and practice, movements appropriately. Here we investigated how power training (i.e., high-intensity, dynamic resistance training) affects recovery of upper-extremity motor function post-stroke. We hypothesized that power training, as a component of upper-extremity rehabilitation, would promote greater functional gains than functional task practice without deleterious consequences.

Method

Nineteen chronic hemiparetic individuals were studied using a crossover design. All participants received both functional task practice (FTP) and HYBRID (combined FTP and power training) in random order. Blinded evaluations performed at baseline, following each intervention block and 6-months post-intervention included: Wolf Motor Function Test (WMFT-FAS, Primary Outcome), upper-extremity Fugl-Meyer Motor Assessment, Ashworth Scale, and Functional Independence Measure. Neuromechanical function was evaluated using isometric and dynamic joint torques and concurrent agonist EMG. Biceps stretch reflex responses were evaluated using passive elbow stretches ranging from 60 to 180º/s and determining: EMG onset position threshold, burst duration, burst intensity and passive torque at each speed.

Results

Primary outcome: Improvements in WMFT-FAS were significantly greater following HYBRID vs. FTP (p?=?.049), regardless of treatment order. These functional improvements were retained 6-months post-intervention (p?=?.03). Secondary outcomes: A greater proportion of participants achieved minimally important differences (MID) following HYBRID vs. FTP (p?=?.03). MIDs were retained 6-months post-intervention. Ashworth scores were unchanged (p?>?.05). Increased maximal isometric joint torque, agonist EMG and peak power were significantly greater following HYBRID vs. FTP (p < .05) and effects were retained 6-months post-intervention (p’s?<?.05). EMG position threshold and burst duration were significantly reduced at fast speeds (≥120º/s) (p’s < 0.05) and passive torque was reduced post-washout (p < .05) following HYBRID.

Conclusions

Functional and neuromechanical gains were greater following HYBRID vs. FPT. Improved stretch reflex modulation and increased neuromuscular activation indicate potent neural adaptations. Importantly, no deleterious consequences, including exacerbation of spasticity or musculoskeletal complaints, were associated with HYBRID. These results contribute to an evolving body of contemporary evidence regarding the efficacy of high-intensity training in neurorehabilitation and the physiological mechanisms that mediate neural recovery.     

Manual therapy directed at the knee or lumbopelvic region does not influence quadriceps spinal reflex excitability

Manual therapies, directed to the knee and lumbopelvic region, have demonstrated the ability to improve neuromuscular quadriceps function in individuals with knee pathology. It remains unknown if manual therapies may alter impaired spinal reflex excitability, thus identifying a potential mechanism in which manual therapy may improve neuromuscular function following knee injury.AimTo determine the effect of local and distant mobilisation/manipulation interventions on quadriceps spinal reflex excitability.MethodsSeventy-five individuals with a history of knee joint injury and current quadriceps inhibition volunteered for this study. Participants were randomised to one of five intervention groups: lumbopelvic manipulation (grade V), lumbopelvic manipulation positioning (no thrust), grade IV patellar mobilisation, grade I patellar mobilisation, and control (no treatment). Changes in spinal reflex excitability were quantified by assessing the Hoffmann reflex (H-reflex), presynaptic, and postsynaptic excitability. A hierarchical linear-mixed model for repeated measures was performed to compare changes in outcome variables between groups over time (pre, post 0, 30, 60, 90 min).ResultsThere were no significant differences in H-reflex, presynaptic, or postsynaptic excitability between groups across time.ConclusionsManual therapies directed to the knee or lumbopelvic region did not acutely change quadriceps spinal reflex excitability. Although manual therapies may improve impairments and functional outcomes the underlying mechanism does not appear to be related to changes in spinal reflex excitability.     

Effect of Sacroiliac Joint Mobilization on the Level of Soft Tissue Pain Threshold in Asymptomatic Women

Objective

This study aimed to evaluate the effect of sacroiliac joint (SIJ) mobilization and/or self-mobilization on the level of soft tissue pain threshold in 21- to 23-year-old asymptomatic women (n = 20).

Effects of Swedish massage on gait spatiotemporal parameters in adult women with medial knee osteoarthritis: A randomized controlled trial

BackgroundPatients with knee osteoarthritis (OA) are always faced with functional limitations in daily activities due to knee pain. They are also at risk of falling because of compensatory kinetics and kinematics changes in walking, which is why they are seeking complementary therapies to deal with their problems.ObjectiveThe present research aimed to evaluate whether Swedish massage is effective in relieving the symptoms of knee OA and improving the gait spatiotemporal parameters of patients with knee OA.MethodsThirty adult women with knee OA participated in this study voluntarily. The intervention group (n = 15) received Swedish massage on their quadriceps for 20–30 min per session (12 sessions). During this period, the control group (n = 15) received their regular treatment. Osteoarthritis symptoms were evaluated by the Western Ontario and McMaster Universities Osteoarthritis Index. The spatiotemporal parameters of gait were also captured by the motion analysis system during barefoot walking.ResultsThe intervention group demonstrated significantly more pain relief and improved function compared to the control group. A significant increase was observed in the gait speed, total support time, and single support time (P < 0.05). Moreover, there was a significant decrease in the step width and initial double support time of the patients after receiving Swedish massage (P < 0.05).ConclusionIt can be concluded that Swedish massage may positively affect pain relief and function improvement in patients with knee OA. Also, Swedish massage was found to improve the spatiotemporal parameters in the patients. This may have important clinical implications regarding the rehabilitation of patients with knee OA.     

Immediate and Carryover Changes of C5-6 Joint Mobilization on Shoulder External Rotator Muscle Strength

ObjectiveClinical evidence has shown that extremity dysfunction, such as muscle weakness or inhibition, is associated with spinal disorders. Spinal manual therapy is a common therapeutic approach used to address extremity muscle weakness. The purpose of the study was to assess changes in the maximal muscle strength of the shoulder external rotators immediately and at 10, 20, and 30 minutes after cervical joint mobilization at the C5-6 segment.MethodsEighteen participants with existing or a history of neck pain were screened by 2 investigators independently for muscle weakness of shoulder external rotators. Fifteen qualified participants underwent shoulder external rotator strength testing with a handheld dynamometer. Each participant was tested 6 times, twice before, immediately after, and at 10, 20, and 30 minutes after a C5-6 joint mobilization on the involved side. The 2 strength data collected before the mobilization were used to determine intratester reliability.ResultsThe intratester reliability of the shoulder external rotator strength was excellent (intraclass correlation coefficient_3,2 = 0.985). One-way analysis of variance with repeated measures showed a statistical significance in strength data (P = .002). Post hoc tests revealed a significant increase between prejoint mobilization and immediately postjoint mobilization (P = .003) and between pre joint mobilization and 10-minute post joint mobilization (P < .001).ConclusionsThe results of the study suggest that C5-6 joint mobilization increases muscle strength of the shoulder external rotators immediately and its effect carries over for 10 minutes but not after 20 minutes.     

The impact of hearing loss on three-dimensional lower limb joint torques during walking in prepubertal boys

IntroductionIn children, the impact of hearing loss on biomechanical gait parameters is not well understood. Thus, the objectives of this study were to examine three-dimensional lower limb joint torques in deaf compared to age-matched healthy (hearing) children while walking at preferred gait speed.MethodsThirty prepubertal boys aged 8–14 were enrolled in this study and divided into a group with hearing loss (deaf group) and an age-matched healthy control. Three-dimensional joint torques were analyzed during barefoot walking at preferred speed using Kistler force plates and a Vicon motion capture system.ResultsFindings revealed that boys with hearing loss showed lower joint torques in ankle evertors, knee flexors, abductors and internal rotators as well as in hip internal rotators in both, the dominant and non-dominant lower limbs (all p < 0.05; d = 1.23–7.00; 14–79%). Further, in the dominant limb, larger peak ankle dorsiflexor (p < 0.001; d = 1.83; 129%), knee adductor (p < 0.001; d = 3.20; 800%), and hip adductor torques (p < 0.001; d = 2.62; 350%) were found in deaf participants compared with controls.ConclusionThe observed altered lower limb torques during walking are indicative of unstable gait in children with hearing loss. More research is needed to elucidate whether physical training (e.g., balance and/or gait training) has the potential to improve walking performance in this patient group.     

Correlation of plasma and synovial fluid osteopontin with disease severity in knee osteoarthritis

Objectives

The purposes of this study were to examine osteopontin levels in both plasma and synovial fluid of patients with primary knee osteoarthritis (OA) and to investigate their relationship with severity of the disease.

Design and methods

Thirty-two patients aged 53-83 years with knee OA and 15 healthy controls were enrolled in this study. Anteroposterior knee radiographs were taken to determine the disease severity of the affected knee. The radiographic grading of OA in the knee was performed by using the Kellgren-Lawrence criteria. Osteopontin levels in the plasma and synovial fluid were measured using enzyme-linked immunosorbent assay.

Results

The mean plasma osteopontin concentration of the knee OA patients was significantly higher compared with that of healthy controls (168.8 ± 15.6 vs 67.2 ± 7.7 ng/mL, P < 0.0001). Osteopontin levels in synovial fluid were significantly higher with respect to paired plasma samples (272.1 ± 15.0 vs 168.8 ± 15.6 ng/mL, P < 0.001). In addition, plasma osteopontin levels showed a positive correlation with synovial fluid osteopontin levels (r = 0.373, P = 0.035). Subsequent analysis showed that plasma osteopontin levels significantly correlated with severity of disease (r = 0.592, P < 0.001). Furthermore, the synovial fluid levels of osteopontin also correlated with disease severity (r = 0.451, P = 0.01).

Conclusion

The data suggest that osteopontin in plasma and synovial fluid is related to progressive joint damage in knee OA. Osteopontin may serve as a biochemical marker for determining disease severity and could be predictive of prognosis with respect to the progression of knee OA.     

Influence of Lumbar Mobilizations During the Nordic Hamstring Exercise on Hamstring Measures of Knee Flexor Strength,Failure Point,and Muscle Activity: A Randomized Crossover Trial

ObjectiveThe aims of this study were to quantify the effects of spinal mobilization on force production, failure point, and muscle activity of the hamstrings during the Nordic hamstring exercise (NHE), and to explore individual differences in responses.MethodsIn a replicated randomized crossover trial, 24 asymptomatic, recreationally active men (age [mean ± standard deviation]: 27 ± 6 years; body mass: 82 ± 17 kg; height: 181 ± 8 cm) completed 2 standardized intervention trials (L4/5 zygapophyseal mobilizations) and 2 control trials. The failure point of the NHE was determined with 3D motion capture. Peak force, knee flexor torque, and electromyography (EMG) of the biceps femoris were measured. Data analyses were undertaken to quantify mean intervention response and explore any individual response heterogeneity.ResultsMean (95% confidence interval) left-limb force was higher in intervention than in control trials by 18.7 (4.6-32) N. Similarly, right-limb force was higher by 22.0 (3.4-40.6) N, left peak torque by 0.14 (0.06-0.22) N ? m, and right peak torque by 0.14 (0.05-0.23) N ? m/kg. Downward force angle was decreased in intervention vs control trials by 4.1° (0.5°-7.6°) on the side of application. Both peak EMG activity (P = .002), and EMG at the downward force (right; P = .020) increased in the intervention condition by 16.8 (7.1-26.4) and 8.8 (1.5-16.1) mV, respectively. Mean downward acceleration angle changed by only 0.3° (?8.9° to 9.4°) in intervention vs control trials. A clear response heterogeneity was indicated only for right force (Participant × Intervention interaction: P = .044; response heterogeneity standard deviation = 34.5 [5.7-48.4] N). Individual response heterogeneity was small for all other outcomes.ConclusionAfter spinal mobilization, immediate changes in bilateral hamstring force production and peak torque occurred during the NHE. The effect on the NHE failure point was unclear. Electromyographic activity increased on the ipsilateral side. Response heterogeneity was generally similar to the random trial-to-trial variability inherent in the measurement of the outcomes.     

No Exacerbation of Knee Joint Pain and Effusion Following Preoperative Progressive Resistance Training in Patients Scheduled for Total Knee Arthroplasty: Secondary Analyses From a Randomized Controlled Trial

Background

Preoperative progressive resistance training (PRT) is controversial in patients scheduled for total knee arthroplasty (TKA), because of the concern that it may exacerbate knee joint pain and effusion.