Factors associated with fatigue in hip and/or knee osteoarthritis: a systematic review and best evidence synthesis.

OBJECTIVE: The aim was systematically to identify and evaluate factors related to fatigue in individuals with hip and/or knee OA. METHODS: A systematic literature search was conducted using AMED, CINAHL, MEDLINE, ProQuest and Web of Science Core Collections databases. Inclusion criteria comprised cross-sectional, case-control or longitudinal studies on patients with a diagnosis of hip and/or knee OA that included self-reported fatigue measures. Study quality was assessed using the National Heart, Lung and Blood Institute quality appraisal tool, and factors were synthesized within a bio-behavioural framework. Study designs and quality were combined to determine current evidence levels using best evidence synthesis grading. The full review protocol is available from PROSPERO (PROSPERO 2019: CRD42019138571). RESULTS: Twenty-four studies were included, of which 19 were high, 4 moderate and 1 low quality. There was strong evidence of an association between poor self-reported physical function and high depressive symptoms with higher fatigue. Moderate evidence of an association was found between severe pain, high numbers of co-morbidities and low physical activity levels with higher fatigue. There was moderate or limited evidence of no association between most sociodemographic factors and radiographic OA severity with fatigue. CONCLUSION: Targets for fatigue management might include improving physical function, reducing depressive symptoms, pain and co-morbidities, and increasing physical activity levels. There is a need for more rigorous longitudinal studies to understand the causal effect of fatigue determinants within the hip and knee OA populations.

Foot characteristics and mechanics in individuals with knee osteoarthritis: systematic review and meta-analysis.

BACKGROUND: Foot characteristics and mechanics are hypothesized to affect aetiology of several lower extremity musculoskeletal conditions, including knee osteoarthritis (KOA). The purpose of this systematic review was to identify the foot characteristics and mechanics of individuals with KOA. METHODS: Five databases were searched to identify relevant studies on foot characteristics and mechanics in people with KOA. Meta-analyses were performed where common measures were found across included studies. Included studies were evaluated for data reporting quality using the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) checklist. RESULTS: Thirty-nine studies were included in this systematic review. Two studies reported participants with KOA had statistically significantly (P < 0.05) more pronated foot postures than those without. Meta-analyses for foot progression angle (FPA) and peak rearfoot eversion angle found no difference between those with and without KOA (FPA mean difference:-1.50 [95% confidence interval - 4.20-1.21]; peak rearfoot eversion mean difference: 0.71 [1.55-2.97]). CONCLUSION: A more pronated foot posture was noticed in those with KOA. However, it was not possible to establish a relationship between other foot characteristics or mechanics in people with KOA due to heterogeneity between the included study and limited number of studies with similar measurements. There is need for identifying common measurement techniques and reporting metrics when studying the foot in those with KOA.

Determinants of generalized fatigue in individuals with symptomatic knee osteoarthritis: The MOST Study.

AIM: The aim of the study was to identify sociodemographic, disease-related, physical and mental health-related determinants of fatigue at 2-year follow-up in individuals with symptomatic knee osteoarthritis (OA). METHODS: A longitudinal analysis of participants with symptomatic knee OA from the Multicenter Osteoarthritis Study (MOST) was conducted to identify predictors of fatigue at 2-year follow-up. Participants self-reported fatigue at baseline for the first time in the MOST cohort and at follow-up using a 0-10 visual analog scale. At baseline, questionnaires on sociodemographics, disease-related symptoms, physical and mental health factors were completed. Data were analyzed using linear regressions with a backwards elimination approach. RESULTS: Of the 2330 individuals in the MOST cohort at baseline, 576 had symptomatic knee OA and of these, 449 with complete fatigue values at baseline and follow-up were included in this analysis. Minimally important fatigue change (ie, worsening [≥1.13], no change [<0.82 or <1.13] and improvement [≥-0.82]) from baseline to follow-up were unequal within the population (34.5%, 26.9%, 38.5%; χ2 [2, N = 449] = 9.32, P = .009). The multiple linear regression showed that baseline fatigue (unstandardized coefficient [Β] = 0.435; 95% confidence interval [CI] 0.348-0.523, P < .001), slow gait speed (Β = -1.124; 95% CI -1.962 to -0.285, P = .009), depressive symptoms (Β = 0.049; 95% CI 0.024-0.075, P < .001) and higher numbers of comorbidities (Β = 0.242; 95% CI 0.045-0.439, P = .016) were significant predictors of greater fatigue at follow-up. CONCLUSION: Fatigue is strongly associated with physical- and mental-related health factors. Individualized treatments that include combined psychological and physical function rehabilitation might be modalities for fatigue management.

A systematic review of economic evaluations of conservative treatments for chronic lower extremity musculoskeletal complaints.

OBJECTIVE: The aim was to appraise and synthesize studies evaluating the clinical and cost effectiveness of conservative interventions for chronic lower extremity musculoskeletal (MSK) conditions and describe their characteristics, including the type of economic evaluation, primary outcomes and which conditions. METHODS: The search strategy related to economic evaluations of lower limb MSK conditions that used conservative therapies. Eight electronic databases were searched (CENTRAL, MEDLINE, PubMed, EMBASE, CINAHL, PEDro, NHSEED and Proquest), as were the reference lists from included articles. The quality of articles was appraised using a modified version of the economic evaluations' reporting checklist (economic) and The Cochrane Collaboration's tool for assessing risk of bias (clinical). RESULTS: Twenty-six studies were eligible and included in the review. Economic evaluations of conservative interventions for OA or pain affecting the knee/hip (n = 25; 93%) were most common. The main approaches adopted were cost-utility analysis (n = 17; 68%) or cost-effectiveness analysis (n = 5; 19%). Two studies involved interventions including footwear/foot orthoses; for heel pain (n = 1; 4%) and overuse injuries (n = 1; 4%). Fifty per cent of economic evaluations adopted the EQ-5D-3L as the primary outcome measure for quality of life and quality-adjusted life year calculations. CONCLUSION: Economic evaluations have been conducted largely for exercise-based interventions for MSK conditions of the hip and knee. Few economic evaluations have been conducted for other clinically important lower limb MSK conditions. A matrix presentation of costs mapped with outcomes indicated increasing costs with either no difference or improvements in clinical effectiveness. The majority of economic evaluations were of good reporting quality, as were the accompanying clinical studies.

Prevalence and course of lower limb disease activity and walking disability over the first 5 years of juvenile idiopathic arthritis: results from the childhood arthritis prospective study.

OBJECTIVE: The aim was to investigate the time course of lower limb disease activity and walking disability in children with JIA over a 5-year course. METHODS: The Childhood Arthritis Prospective Study is a longitudinal study of children with a new JIA diagnosis. Childhood Arthritis Prospective Study data include demographics and core outcome variables at baseline, 6 months and yearly thereafter. Prevalence and transition rates from baseline to 5 years were obtained for active and limited joint counts at the hip, knee, ankle and foot joints; and walking disability, measured using the Childhood Health Assessment Questionnaire walking subscale. Missing data were accounted for using multiple imputation. RESULTS: A total of 1041 children (64% female), with a median age of 7.7 years at first visit, were included. Baseline knee and ankle synovitis prevalence was 71 and 34%, respectively, decreasing to 8-20 and 6-12%, respectively, after 1 year. Baseline hip and foot synovitis prevalence was <11%, decreasing to <5% after 6 months. At least mild walking disability was present in 52% at baseline, stabilizing at 25-30% after 1 year. CONCLUSION: Lower limb synovitis and walking disability are relatively common around the time of initial presentation in children and young people with JIA. Mild to moderate walking disability persisted in ∼25% of patients for the duration of the study, despite a significant reduction in the frequency of lower limb synovitis. This suggests that there is an unmet need for non-medical strategies designed to prevent and/or resolve persistent walking disability in JIA.

The Effects of Tai Chi on Peripheral Somatosensation, Balance, and Fitness in Hispanic Older Adults with Type 2 Diabetes: A Pilot and Feasibility Study.

Peripheral neuropathy and loss of somatosensation in older adults with type 2 diabetes can increase risk of falls and disability. In nondiabetic older adult population Tai Chi has been shown to enhance balance and fitness through improvements in somatosensation and neuromuscular control, and it is unclear if Tai Chi would elicit similar benefits in older adults with diabetes. Therefore, the purpose of this study was to investigate the effects of an 8-week, three-hour-per-week Tai Chi intervention on peripheral somatosensation in older adults with type 2 diabetes. Participants were eight Hispanic older adults with type 2 diabetes who participated in the Tai Chi intervention and a convenience sample of Hispanic older adults as a referent group. Baseline and postintervention assessments included ankle proprioception, foot tactile sense, plantar pressure distribution, balance, and fitness. After intervention, older adults with type 2 diabetes showed significant improvements in ankle proprioception and fitness and decreased plantar pressure in the forefoot, with no statistical effect noted in balance or tactile sensation. Study results suggest that Tai Chi may be beneficial for older adults with diabetes as it improves ankle proprioception; however, study findings need to be confirmed in a larger sample size randomized controlled trial.

Teaching undergraduate biomechanics with Just-in-Time Teaching.

Biomechanics education is a vital component of kinesiology, sports medicine, and physical education, as well as for many biomedical engineering and bioengineering undergraduate programmes. Little research exists regarding effective teaching strategies for biomechanics. However, prior work suggests that student learning in undergraduate physics courses has been aided by using the Just-in-Time Teaching (JiTT). As physics understanding plays a role in biomechanics understanding, the purpose of study was to evaluate the use of a JiTT framework in an undergraduate biomechanics course. This two-year action-based research study evaluated three JiTT frameworks: (1) no JiTT; (2) mathematics-based JiTT; and (3) concept-based JiTT. A pre- and post-course assessment of student learning used the biomechanics concept inventory and a biomechanics concept map. A general linear model assessed differences between the course assessments by JiTT framework in order to evaluate learning and teaching effectiveness. The results indicated significantly higher learning gains and better conceptual understanding in a concept-based JiTT course, relative to a mathematics-based JiTT or no JiTT course structure. These results suggest that a course structure involving concept-based questions using a JiTT strategy may be an effective method for engaging undergraduate students and promoting learning in biomechanics courses.

Associations of Region-Specific Foot Pain and Foot Biomechanics: The Framingham Foot Study.

BACKGROUND: Specific regions of the foot are responsible for the gait tasks of weight acceptance, single-limb support, and forward propulsion. With region foot pain, gait abnormalities may arise and affect the plantar pressure and force pattern utilized. Therefore, this study's purpose was to evaluate plantar pressure and force pattern differences between adults with and without region-specific foot pain. METHODS: Plantar pressure and force data were collected on Framingham Foot Study members while walking barefoot at a self-selected pace. Foot pain was evaluated by self-report and grouped by foot region (toe, forefoot, midfoot, or rearfoot) or regions (two or three or more regions) of pain. Unadjusted and adjusted linear regression with generalized estimating equations was used to determine associations between feet with and without foot pain. RESULTS: Individuals with distal foot (forefoot or toes) pain had similar maximum vertical forces under the pain region, while those with proximal foot (rearfoot or midfoot) pain had different maximum vertical forces compared to those without regional foot pain (referent). During walking, there were significant differences in plantar loading and propulsion ranging from 2% to 4% between those with and without regional foot pain. Significant differences in normalized maximum vertical force and plantar pressure ranged from 5.3% to 12.4% and 3.4% to 24.1%, respectively, between those with and without regional foot pain. CONCLUSIONS: Associations of regional foot pain with plantar pressure and force were different by regions of pain. Region-specific foot pain was not uniformly associated with an increase or decrease in loading and pressure patterns regions of pain.

Associations of socioeconomic position and pain prevalence in the United States: findings from the National Health and Nutrition Examination Survey.

BACKGROUND: Pain is a significant burden within the U.S. adult population, but little is known regarding epidemiology of pain, particularly with respect to race, ethnicity, and socioeconomic position (SEP). OBJECTIVE: The purpose of this study was to describe and evaluate prevalence and distribution of pain in the United States. METHODS: With data from the population-based 2003-2004 National Health and Nutrition Examination Survey, prevalence of acute (<3 months) and chronic (≥ 3 months) pain was evaluated, including subgroup analyses of race, ethnicity, and SEP, with SEP defined by the poverty-to-income ratio, a ratio derived from the federal poverty level, accounting for household income and number of household members. RESULTS: Prevalence of acute pain was 12.2% (95% confidence interval: 11.2-13.3%). Non-Hispanic black as well as Hispanic and Mexican-American individuals had higher rates of acute pain than non-Hispanic white people, and a higher prevalence was noted in those with higher SEP. Chronic pain prevalence was 15.6% (13.4-17.7%), with non-Hispanic white people having a higher prevalence than those in other racial and ethnic groups. CONCLUSION: Trends of chronic pain by SEP were opposite of acute pain as those in the highest SEP group tended to have less chronic pain than those in lower SEP groups. These findings suggest that SEP, in addition to race and ethnicity, may play a role in the development of pain as well as its treatment and management.

Hallux valgus and plantar pressure loading: the Framingham foot study.

BACKGROUND: Hallux valgus (HV), a common structural foot deformity, can cause foot pain and lead to limited mobility. The purpose of this study was to evaluate differences in plantar pressure and force during gait by HV status in a large population-based cohort of men and women. METHODS: A trained examiner performed a validated physical examination on participants' feet and recorded the presence of hallux valgus and other specific foot disorders. Each foot was classified into one of four mutually exclusive groups based on the foot examination. Foot groups were: (i) HV only, (ii) HV and at least one additional foot disorder (FD), (iii) no HV but at least one other FD, and (iv) neither HV nor FD (referent). Biomechanical data for both feet were collected using Tekscan Matscan. Foot posture during quiet standing, using modified arch index (MAI), and foot function during gait, using center of pressure excursion index (CPEI), were calculated per foot. Further, walking scans were masked into eight sub-regions using Novel Automask, and peak pressure and maximum force exerted in each region were calculated. RESULTS: There were 3205 participants, contributing 6393 feet with complete foot exam data and valid biomechanical measurements. Participants with HV had lower hallucal loading and higher forces at lesser toes as well as higher MAI and lower CPEI values compared to the referent. Participants with HV and other FDs were also noted to have aberrant rearfoot forces and pressures. CONCLUSIONS: These results suggest that HV alters foot loading patterns and pressure profiles. Future work should investigate how these changes affect the risk of other foot and lower extremity ailments.

Foot posture, foot function and low back pain: the Framingham Foot Study.

OBJECTIVE: Abnormal foot posture and function have been proposed as possible risk factors for low back pain, but this has not been examined in detail. The objective of this study was to explore the associations of foot posture and foot function with low back pain in 1930 members of the Framingham Study (2002-05). METHODS: Low back pain, aching or stiffness on most days was documented on a body chart. Foot posture was categorized as normal, planus or cavus using static weight-bearing measurements of the arch index. Foot function was categorized as normal, pronated or supinated using the centre of pressure excursion index derived from dynamic foot pressure measurements. Sex-specific multivariate logistic regression models were used to examine the associations of foot posture, foot function and asymmetry with low back pain, adjusting for confounding variables. RESULTS: Foot posture showed no association with low back pain. However, pronated foot function was associated with low back pain in women [odds ratio (OR) = 1.51, 95% CI 1.1, 2.07, P = 0.011] and this remained significant after adjusting for age, weight, smoking and depressive symptoms (OR = 1.48, 95% CI 1.07, 2.05, P = 0.018). CONCLUSION: These findings suggest that pronated foot function may contribute to low back symptoms in women. Interventions that modify foot function, such as orthoses, may therefore have a role in the prevention and treatment of low back pain.

Foot disorders, foot posture, and foot function: the Framingham foot study.

INTRODUCTION: Foot disorders are common among older adults and may lead to outcomes such as falls and functional limitation. However, the associations of foot posture and foot function to specific foot disorders at the population level remain poorly understood. The purpose of this study was to assess the relation between specific foot disorders, foot posture, and foot function. METHODS: Participants were from the population-based Framingham Foot Study. Quintiles of the modified arch index and center of pressure excursion index from plantar pressure scans were used to create foot posture and function subgroups. Adjusted odds ratios of having each specific disorder were calculated for foot posture and function subgroups relative to a referent 3 quintiles. RESULTS: Pes planus foot posture was associated with increased odds of hammer toes and overlapping toes. Cavus foot posture was not associated with the foot disorders evaluated. Odds of having hallux valgus and overlapping toes were significantly increased in those with pronated foot function, while odds of hallux valgus and hallux rigidus were significantly decreased in those with supinated function. CONCLUSIONS: Foot posture and foot function were associated with the presence of specific foot disorders.

Association of planus foot posture and pronated foot function with foot pain: the Framingham foot study.

OBJECTIVE: To examine the associations of foot posture and foot function to foot pain. METHODS: Data were collected on 3,378 members of the Framingham Study cohort who completed foot examinations in 2002-2008. Foot pain (generalized and at 6 locations) was based on the response to the following question: "On most days, do you have pain, aching or stiffness in either foot?" Foot posture was categorized as normal, planus, or cavus using static pressure measurements of the arch index. Foot function was categorized as normal, pronated, or supinated using the center of pressure excursion index from dynamic pressure measurements. Sex-specific multivariate logistic regression models were used to examine the effect of foot posture and function on generalized and location-specific foot pain, adjusting for age and weight. RESULTS: Planus foot posture was significantly associated with an increased likelihood of arch pain in men (odds ratio [OR] 1.38, 95% confidence interval [95% CI] 1.01-1.90), while cavus foot posture was protective against ball of foot pain (OR 0.74, 95% CI 0.55-1.00) and arch pain (OR 0.64, 95% CI 0.48-0.85) in women. Pronated foot function was significantly associated with an increased likelihood of generalized foot pain (OR 1.28, 95% CI 1.04-1.56) and heel pain (OR 1.54, 95% CI 1.04-2.27) in men, while supinated foot function was protective against hindfoot pain in women (OR 0.74, 95% CI 0.55-1.00). CONCLUSION: Planus foot posture and pronated foot function are associated with foot symptoms. Interventions that modify abnormal foot posture and function may therefore have a role in the prevention and treatment of foot pain.

Factors affecting center of pressure in older adults: the Framingham Foot Study.

BACKGROUND: Although aberrant foot movement during gait has been associated with adverse outcomes in the lower extremities in clinical patients, few studies have analyzed population differences in foot function. The purpose of this study was to assess demographic differences in foot function in a large population-based study of community-dwelling adults. METHODS: Participants in this study were from the Framingham Foot Study. Walking data were collected from both feet using a Tekscan Matscan pressure mat. Foot function was characterized using the center of pressure excursion index (CPEI). T-tests were used to assess differences between population subsets based on sex, and in men and women separately, age, body mass index (BMI), physical activity and in women, past high heel use. RESULTS: There were 2111 participants included in this analysis. Significant differences in CPEI were noted by sex (p< 0.0001), by age in women (p = 0.04), and by past high heel use in women (p = 0.04). CONCLUSIONS: Foot function during gait was affected by sex, as well as by age and shoe-wear in women, but not by BMI or physical activity. Future work will evaluate possible relations between CPEI and outcomes such as falls, sarcopenia, and lower extremity function.

Foot pain and mobility limitations in older adults: the Framingham Foot Study.

BACKGROUND: Foot pain is very common in the general population and has been shown to have a detrimental impact on health-related quality of life. This is of particular concern in older people as it may affect activities of daily living and exacerbate problems with balance and gait. The objective of this study is to evaluate the independent relationships between foot pain and mobility limitation in a population of community-dwelling older adults. METHODS: Population-based cross-sectional study. Participants (n = 1,544) from the Framingham Foot Study (2002-2008) were assessed for physical performance. Foot pain was documented using the question "On most days, do you have pain, aching, or stiffness in either foot?" Mobility limitation was assessed using the Short Physical Performance Battery, dichotomized using 1-9 as an indicator of mobility limitation and 10-12 as no mobility limitation. RESULTS: Foot pain was reported by 19% of men and 25% of women. After adjusting for age, obesity, smoking status, and depression, foot pain was significantly associated with mobility limitation in both men (odds ratio = 2.00, 95% confidence interval 1.14 - 3.50; p = .016) and women (odds ratio = 1.59, 95% confidence interval 1.03 - 2.46; p = .037). CONCLUSION: In our study of older adults from the Framingham Foot Study, foot pain was associated with an increased odds of having mobility limitation in both men and women. Clinicians should consider assessment of foot pain in general examinations of older adults who are at risk of mobility limitation.

Associations of foot posture and function to lower extremity pain: results from a population-based foot study.

OBJECTIVE: Studies have implicated foot posture and foot function as risk factors for lower extremity pain. Empirical population-based evidence for this assertion is lacking; therefore, the purpose of this study was to evaluate cross-sectional associations of foot posture and foot function to lower extremity joint pain in a population-based study of adults. METHODS: Participants were members of the Framingham Foot Study. Lower extremity joint pain was determined by the response to the National Health and Nutrition Examination Survey-type question, "On most days do you have pain, aching or stiffness in your (hips, knees, ankles, or feet)?" The Modified Arch Index classified participants as having planus, rectus (referent), or cavus foot posture. The Center of Pressure Excursion Index classified participants as having overpronated, normal (referent), or oversupinated foot function. Crude and adjusted (age, sex, and body mass index) logistic regression determined associations of foot posture and function to lower extremity pain. RESULTS: Participants with planus structure had higher odds of knee (odds ratio [OR] 1.57, 95% confidence interval [95% CI] 1.24-1.99) or ankle (OR 1.47, 95% CI 1.05-2.06) pain, whereas those with a cavus foot structure had increased odds of ankle pain only (OR 7.56, 95% CI 1.99-28.8) and pain at 1 lower extremity site (OR 1.37, 95% CI 1.04-1.80). Associations between foot function and lower extremity joint pain were not statistically significant except for a reduced risk of hip pain in those with an oversupinated foot function (OR 0.69, 95% CI 0.51-0.93). CONCLUSION: These findings offer a link between foot posture and lower extremity pain, highlighting the need for longitudinal or intervention studies.

Musculoskeletal conditions of the foot and ankle: assessments and treatment options.

Musculoskeletal conditions of the foot and ankle are an important public health challenge due to their increasing incidence combined with their substantial negative impact on patients' quality of life. Non-pharmacological treatments serve as the first line of treatment and are frequently used for patients with musculoskeletal conditions of the foot and ankle. This review provides a summary of the assessments and non-invasive treatment options based upon available evidence. Recent studies show that individuals with foot and ankle pain have multiple co-existing impairments in alignment, motion, load distribution and muscle performance that may be evident in static and/or dynamic tasks. In addition, both clinical and epidemiological studies support the inter-dependence between the foot and proximal joints. For instance, aberrant foot structure has been linked to foot osteoarthritis (OA), as well as OA and pain at the knee and hip. Most recently, advances in motion capture technology and plantar load distribution measurement offer opportunities for precise dynamic assessments of the foot and ankle. In individuals with musculoskeletal conditions of the foot and ankle, the chief objectives of treatment are to afford pain relief, restore mechanics (alignment, motion and/or load distribution) and return the patient to their desired level of activity participation. Given that most patients present with multiple impairments, combinational therapies that target foot-specific as well as global impairments have shown promising results. In particular, in individuals with rheumatoid arthritis and other rheumatic diseases, comprehensive rehabilitation strategies including early detection, foot-based interventions (such as orthoses) and wellness-based approaches for physical activity and self-management have been successful. While significant improvements have been made in the last decade to the assessment and treatment of foot and ankle conditions, few randomised clinical trials specifically have investigated patients with foot or ankle conditions to provide global insights into this area. Consequently, current recommendations vary based upon the scope of studies presented in this review as well as the strength of studies. This review indicates a need for more in-depth investigations into the components of assessment and treatment options for foot and ankle musculoskeletal conditions.

Gait and neuromuscular adaptations after using a feedback-based gait monitoring knee brace.

PURPOSE: The purpose of this study was to evaluate the gait and neuromuscular effects of a feedback-based gait monitoring knee brace. The aim of this paper was to explore how training with this knee brace affected the gait pattern utilized, rate of loading (ROL), and proprioceptive acuity. METHODS: Fifteen healthy women wore this knee brace that provided audible feedback on gait kinematics for a 30-min training period. We performed pre- and post-gait analyses and proprioceptive acuity assessments to determine gait learning and adaptation with this training. RESULTS: Post-training significant changes were seen in the knee angle prior to and at initial contact and peak knee extensor, flexor, and adductor moments, which ultimately led to a reduced ROL experienced. Subjects also had improved proprioceptive acuity post-training. INTERPRETATIONS: Our results indicate that using a feedback-based gait monitoring knee brace can change the gait pattern by increasing the knee flexion angle during the swing to stance transition. Though there was an approximate 25% decrease in the ROL experienced, there was also an increase in the knee adductor moment. Future long-term studies are needed to further explore the positive and negative effects of feedback-based gait monitoring knee brace on individuals with a compromised knee joint, such as those post-anterior cruciate ligament injury.

Effects of quadriceps and hamstrings proprioceptive neuromuscular facilitation stretching on knee movement sensation.

Stretching before competition has traditionally been thought to benefit performance; however, recent evidence demonstrating reduced muscle force and power immediately after stretching suggests otherwise. We hypothesized that knee joint position sense would be diminished immediately after proprioceptive neuromuscular facilitation (PNF) stretching to the hamstrings and quadriceps. Eighteen subjects (aged 18-30 years) were seated with their dominant foot attached to a motorized arm with the knee flexed at 135 degrees . To block external cues, the subjects wore a blindfold, earplugs, and headphones providing white noise. The knee was displaced in either the flexion or the extension direction at a velocity of 0.4 degrees .s, and subjects pressed a button when they sensed motion. The knee was returned to 135 degrees , and the test was repeated for a total of 10 trials. The PNF group received PNF stretching to the hamstrings and quadriceps of the dominant leg. The SHAM group had the dominant leg passively moved within each subject's functional range of motion. The ability to detect knee movement was retested in the PNF and SHAM groups. Pre- and posttest latencies between movement onset and subject response were analyzed. Results indicated that the PNF group had significantly increased latencies after stretching (from 2.56 +/- 0.83 to 3.46 +/- 1.90 seconds) compared with the SHAM group (3.93 +/- 2.40 to 3.72 +/- 2.15 seconds). It is concluded that PNF stretching of the hamstrings and quadriceps may acutely diminish sensitivity to knee movement. For coaches and trainers, these findings are consistent with previous reports of loss in muscle force and power immediately after stretching, suggesting that stretching just before competition may diminish performance.