Omega 3 fatty acid supplementation improves physical performance: a systematic review and meta-analysis of RCTs

Background

Omega 3 polyunsaturated fatty acids (n-3, PUFA) show promise for improving muscle mass, strength and measures of physical performance that may ameliorate sarcopenia.

Purpose

To perform an updated meta-analysis of n-3 interventions with detailed subgroup analysis on physical performance/strength and muscle mass, with sub-group analysis on duration, age, BMI, sex, and location, amongst others.

Methods

We followed The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) –checklist for systematic reviews and meta-analysis. Literature was searched (ISI, Scopus and PubMed databases up to October 2021) with terms related to n-3 (alpha linolenic acid, docosahexaenoic acid, eicosapentaenoic acid, fish oil etc.) muscle mass, strength and physical performance (using the 30 s Chair Stand Test [30CST] for muscle strength and endurance and the Timed Up an Go Test [TUG] for physical performance; both are useful and simple tools that can be used to assess sarcopenia). Human n-3 randomised controlled trials (RCTs) were included and assessed for methodological quality (Cochrane quality assessment tool). Weighted mean differences (WMDs) with 95% confidence intervals (CIs) and random-effect model analysis, and I-squared (I2) statistic were used to assess outcomes and heterogeneity respectively. Subgroup and sensitivity analysis were performed, and Begg's and Egger's tests evaluated publication bias. Statistical analysis used STATA 11 software and a p-value of <0.05 was considered statistically significant.

Results

The primary meta-analyses for functional performance (TUG, 7 RCTs, 8 interventions, n=259) and strength (30CST, 5 RCTs, 6 interventions, n=180), favoured n-3 PUFA (p<0.001). TUG (weighted mean change (WMD): −0.35 s; 95% CI: −0.53, −0.18; I2=0.0%) (Figure 1A) and 30CST (WMD: 2.23 repetitions; 95% CI: 1.34, 3.32; I2=67.6%) (Figure 1B). Subgroup analysis for TUG was significant for female sex (WMD: 2.92 reps; 95% CI: 2.37, 3.46; I2=33.1%), BMI ≥25 kg/m2 (WMD: −0.36 s; 95% CI: −0.58, −0.17; I2=16.9%), and for 30CST by duration ≥16 weeks (WMD: 2.60 reps; 95% CI: 1.37, 3.83; I2=0.0%) (all p<0.001). There were no significant effects on muscle mass and handgrip strength, and subgroup analysis showed negligible influence. Publication bias was minimal and sensitivity analysis did not influence findings.

Conclusions

We showed novel favourable effects of n-3 PUFA on specific measures of strength and physical performance in some populations but not on measures of muscle mass and other strength tests. The beneficial effects of n-3 on these measures may be due to various mechanisms that regulate muscle quality (rather than quantity). Further studies are needed to elucidate the dose, duration and other influential variables.

Funding Acknowledgement

Type of funding sources: None.

Youth running consensus statement: minimising risk of injury and illness in youth runners

Despite the worldwide popularity of running as a sport for children, relatively little is known about its impact on injury and illness. Available studies have focused on adolescent athletes, but these findings may not be applicable to preadolescent and pubescent athletes. To date, there are no evidence or consensus-based guidelines identifying risk factors for injury and illness in youth runners, and current recommendations regarding suitable running distances for youth runners at different ages are opinion based. The International Committee Consensus Work Group convened to evaluate the current science, identify knowledge gaps, categorise risk factors for injury/illness and provide recommendations regarding training, nutrition and participation for youth runners.

Forefoot Striking Is More Effective in Reducing Loadrates than Increasing Cadence in Runners

Category:

Sports

Introduction/Purpose:

Vertical impact forces are highly influenced by the way the foot contacts the ground. These impact forces are associated with high loading rates which have been related to running injuries. As a result, clinicians have begun to use gait retraining interventions to reduce loadrates and prevent future impact-related injuries. Two types of gait retraining techniques have been promoted to reduce excessive running impacts. The first involves increasing cadence (CAD), or number of steps per minute, by 5-10%, thereby reducing stride length. The second type of gait retraining involves landing on the ball of the foot at ground contact, or using a forefoot strike (FFS). Both of these gait-retraining styles have been reported to reduce impacts, but they have not been compared with each other.

Methods:

33 healthy runners (9M, 24F), running 5-15 mpw, with a rearfoot strike pattern with cadence < 170 steps/min were recruited. Subjects were randomly allocated to either FFS or CAD retraining. All subjects underwent an 8-session gait retraining program (over 2-3 wks) with auditory feedback on a treadmill. The CAD group ran to a digital metronome to increase cadence by 7.5%. The FFS group wore a wireless accelerometer that provided an auditory signal on footstrike pattern. A gait analysis was conducted at baseline, 1 wk, 1 month, and 6 months. Variables included vertical average and instantaneous load rates (VALR, VILR). A 2 x 4 repeated measures ANOVA was used to compare differences within and between the CAD and FFS groups at baseline, 1 week, 1 month and 6 months post retraining. For variables with significant interactions, simple main effects of group, as well as time were further explored using one-way ANOVA

Results:

There were significant interaction effects of time*group for VALR (p= 0.001), VILR (p=0.001) and foot angle (p< 0.001), but not cadence. For the simple main effects for the CAD group, VALR reduced by 14%, 7% and 16% at 1 week, 1 month, and 6 months post gait retraining respectively, compared with baseline (Figure 1). However, these reductions were not significant. For the FFS group, VALR was significantly reduced by 50%, 51% and 51% at 1 week, 1 month, and 6 months post gait retraining respectively. Interestingly, both the CAD and FFS groups increased cadence by similar amounts.

Conclusion:

Transitioning to a FFS pattern is significantly more effective than increasing CAD when reducing vertical loadrate (both VALR and VILR) is the goal. These changes persisted out to 6 months post gait retraining, suggesting permanence of the new pattern.

The Relationship Between Vertical Loadrates and Tibial Acceleration Across Footstrike Patterns

Category:

Other

Introduction/Purpose:

While the etiology of injuries is multifactorial, impact loading, as measured by the loadrate of the vertical ground reaction force has been implicated. These loadrates are typically measured with a force plate. However, this limits the measure of impacts to laboratory environments. Tibial acceleration, another measure of running impacts, is considered a surrogate for loadrate. It can be measured using new wearable technology that can be used in a runner’s natural environment. However, the correlation between tibial acceleration measured from mobile devices and vertical ground reaction force loadrates, measured from forceplates, is unknown. The purpose of this study was to determine the correlation between vertical and resultant loadrates to vertical and resultant tibial acceleration across different footstrike patterns (FSP) in runners.

Methods:

The study involved a sample of convenience made up of 169 runners (74 F, 95 M; age: 38.66±13.08 yrs) presenting at a running injury clinic. This included 25 habitual forefoot strike (FFS), 17 midfoot strike (MFS) and 127 rearfoot strike (RFS) runners. Participants ran on an instrumented treadmill (average speed 2.52±0.25 m/s), with a tri-axial accelerometer attached at the left distal medial tibia. Only subjects running with pain <3/10 on a VAS scale during the treadmill run were included to reduce the confounding effect of pain. Vertical average, vertical instantaneous and resultant instantaneous loadrates (VALR, VILR and RILR) and peak vertical and resultant tibial accelerations (VTA, RTA) were averaged for 8 consecutive left steps. Correlation coefficients (r) were calculated between tibial accelerations and loadrates.

Results:

All tibial accelerations were significantly correlated across all loadrates, with the exception of RTA with VILR for FFS (Table 1) which was nearly significant (p=0.068). Correlations ranged from 0.37-0.82. VTA was strongly correlated with all loadrates (r = 0.66). RTA was also strongly correlated with both loadrates for RFS and MFS, but only moderately correlated with loadrates for FFS (r = 0.47). Correlations were similar across the different loadrates (VALR, VILR, RILR).

Conclusion:

The stronger correlation between vertical tibial acceleration and all loadrates (VALR, VILR, RILR) suggests that it may be the best surrogate for loadrates when studying impact loading in runners.

Wearable Movement Sensors for Rehabilitation: A Focused Review of Technological and Clinical Advances

Recent technologic advancements have enabled the creation of portable, low-cost, and unobtrusive sensors with tremendous potential to alter the clinical practice of rehabilitation. The application of wearable sensors to track movement has emerged as a promising paradigm to enhance the care provided to patients with neurologic or musculoskeletal conditions. These sensors enable quantification of motor behavior across disparate patient populations and emerging research shows their potential for identifying motor biomarkers, differentiating between restitution and compensation motor recovery mechanisms, remote monitoring, telerehabilitation, and robotics. Moreover, the big data recorded across these applications serve as a pathway to personalized and precision medicine. This article presents state-of-the-art and next-generation wearable movement sensors, ranging from inertial measurement units to soft sensors. An overview of clinical applications is presented across a wide spectrum of conditions that have potential to benefit from wearable sensors, including stroke, movement disorders, knee osteoarthritis, and running injuries. Complementary applications enabled by next-generation sensors that will enable point-of-care monitoring of neural activity and muscle dynamics during movement also are discussed.

Midfoot Strikers Are Different from Forefoot Strikers, but Similar to Rearfoot Strikers

Category:

Sports

Introduction/Purpose:

Rearfoot strike (RFS) patterns have an impact transient that is associated with running injuries. These transients are not present in FFS patterns. Midfoot strike (MFS) runners are often grouped with FFS runners in studies as they are both non-heel strike patterns and assumed to be similar. However, this has not been tested. Tibial shock (TS) provides a measure of impacts and can be easily assessed in the field. Therefore, the purpose of this study was to compare TS among differing footstrike patterns measured during a marathon race. We hypothesized that MFS would have greater impacts than FFS, but lower than RFS. We also aimed to examine how impacts vary across speeds. We hypothesized that impacts would increase with speed similarly in RFS, MFS and FFS.

Methods:

224 healthy runners (119 M, 105 F; 44.1±10.8 yrs) running the 2016 Boston marathon volunteered for the study. Prior to the race, participants ran on a treadmill to determine their habitual footstrike pattern (169 RFS, 32 MFS, 23 FFS). On race day, they ran the course wearing an accelerometer strapped onto their right medial ankle. For this part of the study, the average of the peak TS recorded between the 5 km and 10 km point of the race. This region was used as it had a flat gradient. The peak TS was recorded for each footstrike and averaged over the 5 km distance. This value was compared between the three footstrike patterns using an ANOVA (p<0.05). A regression analysis was used to determine the interaction of FSP and speed for each FSP using individual marathon runner data points. An ANOVA (p<0.05) was used to assess significance of the regression.

Results:

TS in FFS runners was significantly less than in MFS (P=0.01) and RFS (P=0.01) runners. (Figure 1, top panel). There was no difference between RFS and MFS (P=0.49). When examining the relationship between TS and speed, a significant positive correlation was noted for RFS (p<0.00). and MFS (p=0.02), but not for FFS (p=0.82) (Figure 1, bottom panel).

Conclusion:

In contrast to common belief, MFS runners exhibit impacts that are like RFS runners, and both are higher than FFS runners. This suggests that MFS runners should be grouped with RFS runners, and not FFS runners, when assessing impacts. In addition, both RFS and MFS runners exhibited greater impacts as speed increased. However, FFS runners appear to be able to maintain lower impacts at faster speeds. This may be due to greater calf activation, mitigating the effect of increasing speed on impacts. This may offer protection from impact-related injuries in FFS runners.

A Comparison of Foot Strengthening versus Minimal Footwear Use on Intrinsic Muscle Size and Strength

Category:

Other

Introduction/Purpose:

The intrinsic muscles of the arch have been classified as the core of the foot. Intrinsic foot muscles (IFM) work as local stabilizers and extrinsic foot muscles (EFM) work as global movers to help control the pronation of the foot. These muscles prevent excessive strain of the MLA. Previous research has shown that strengthening IFM may reduce pain and improve function in people with plantar fasciitis. Additionally, habitual use of minimal shoes that lack support of the arch require greater demand on the intrinsic muscles. The purpose of this study was to determine the effectiveness of two different strengthening interventions on IFM and EFM size and strength.

Methods:

57 healthy runners (avg 15-30 mpw) were randomly assigned to a foot strengthening (FS, n=19), a minimal shoe walking (MSW, n=19), or a control group (C, n=19). Baseline cross-sectional areas of abductor hallucis, quadratus plantae, flexor digitorum brevis, and flexor digitorum longus, and thickness of the flexor hallucis brevis, tibialis posterior, and tibialis anterior were obtained with ultrasound using a 10 MHz linear probe. Doming, great toe flexion and lateral toes flexion strength were also measured using a custom-built dynamometer. The FS group then underwent an 8 wk foot and ankle strengthening program. The MSW group progressively walked in minimal footwear from 2,500-7,000 over the course of 8 wks. All groups, including C, maintained normal running mileage in conventional footwear throughout the 8 wks. Size and strength measures were then repeated. A repeated measures ANCOVA with a post-hoc test was used to determine differences in size and strength between groups.

Results:

All muscles measured in the FS and MSW groups increased significantly in size from weeks 0-8. There were no changes in muscle size in the C group. The FS group experienced significantly greater size changes for the flexor hallucis brevis than the MSW group. All other changes in muscle size were not significant between the FS and MSW groups. The FS and MSW groups showed significant increases in strength in all 3 tests from week 0-8. Strength of the control group did not change at any time. The increases in strength in the FS and MSW groups were not significantly different than each other.

Conclusion:

Exercises that target the intrinsic and extrinsic foot muscles are effective in increased strength and size of the muscles. However, similar increases in strength and size can be obtained by progressive walking in minimal footwear. Combining both these approaches may have an even greater effect. Stronger feet may offer greater protection against overuse injuries such as plantar fasciitis.

Midfoot Angle Changes During Running After an 8-week Foot Strengthening Program

Category:

Other

Introduction/Purpose:

The arch has been referred to as the core of the foot. The arch’s structure, movement, and integrity during running gait largely depends on the function of intrinsic and extrinsic foot muscles. There are many injuries that can be associated with a dysfunctional medial longitudinal arch. Improving the strength of the foot muscles could help improve arch function during running. The purpose of this study was to compare changes in arch deformation after eight weeks in a foot strengthening exercise group (FS), a group walking in minimalist shoes (MSW), and a control group (C).

Methods:

24 healthy runners (average of 15-30 miles/week, no experience with minimalist footwear) were randomly assigned to FS (n=9), MSW (n=7) or C (n=8). FS subjects followed a series of progressive exercises designed to strengthen the intrinsic and extrinsic foot muscles. MSW subjects walked in minimal footwear, increasing from 2,500 to 7,000 steps/day over an 8 wk period. All runners maintained their pre-study mileage in conventional running shoes throughout the 8-week study Three-dimensional motion analysis data was collected at the beginning of the study and after week 8. Passive-reflective markers were placed according to the Oxford Foot Model. Subjects ran at a self-selected pace on a treadmill while data were collected for at least 10 strides. Peak midfoot angles were extracted and averaged within each trial. Group means at week 0 and week 8 were compared using paired t-tests with alpha set at 0.05.

Results:

While all groups experienced a decrease in midfoot angle, only the FS group experienced a significant change (see table). These results suggest that the foot exercise intervention resulted in more arch control during running than the progressive walking in minimal shoes. Greater changes may have been found if the subjects progressively ran in the minimal shoes which would have placed greater demands on the arch musculature.

Conclusion:

Based on these data, it seems possible for patients to reduce the amount of arch deformation during running by using targeted foot exercises. This could help with patients who have overuse injuries associated with increased arch deformation. These results also suggest that foot strengthening may be an effective way to prepare for minimal footwear running.

The effect of isolated gastrocnemius contracture and gastrocnemius recession on lower extremity kinematics and kinetics during stance

BACKGROUND

Isolated gastrocnemius contracture limits ankle dorsiflexion with full knee extension and is potentially problematic during mid-stance of gait when 10° of dorsiflexion and full knee extension are needed. It is during this time that patients with isolated gastrocnemius contracture may demonstrate altered kinematics and/or kinetics. When conservative management fails to resolve painful foot pathologies associated with non-spastic isolated gastrocnemius contracture, gastrocnemius recession surgery has been suggested to resolve contracture and improve function and strength. However, there are no published reports on lower extremity kinematics/kinetics in the non-spastic isolated gastrocnemius contracture population. Assessment of alterations in gait mechanics is necessary to examine the effects of this potential surgical intervention.

METHODS

Lower extremity kinematics and kinetics were assessed in 6 patients clinically diagnosed with isolated gastrocnemius contracture pre- and post-surgical recession compared with 33 healthy control participants.

FINDINGS

Pre-operatively, patients with isolated gastrocnemius contracture demonstrated significantly increased peak knee flexion angles and knee flexion moments during mid-stance. There were no differences in peak ankle dorsiflexion angle or peak plantar flexion moment. Gastrocnemius recession did not alter gait kinematics/kinetics following surgery. Joint kinematic strategies utilized to compensate for isolated gastrocnemius contracture varied minimally between participants with IGC; most employed a flexed knee strategy, while one participant utilized a reduced ankle dorsiflexion strategy.

INTERPRETATION

Select post-surgical gait mechanics were unaltered; however, gait mechanics were not similar between non-spastic isolated gastrocnemius contracture patients and healthy control participants. Surgical intervention for patients with isolated gastrocnemius contracture does not appear to create any negative gait adaptations; however, patients may benefit from gait retraining post-recession as maladaptive gait patterns persist post operatively.

P3-08-04: “How Important Is This for Me?” – The Role of Necessity Beliefs as Determinants of Breast Cancer Prevention Intentions among High-Risk Women

Background Women at elevated risk for breast cancer (BC) face complex risk management decisions. Understanding the determinants of pre-counselling risk management intentions would be useful to clinicians in helping high-risk women make their decisions. Across several medical conditions, the Necessity-Concerns Framework (NCF) has emphasized the role of patient’ beliefs about interventions offered to them as central to decision-making. In the NCF, beliefs are conceptualized as perceived personal need for an intervention (necessity) and as concerns about its perceived negative effects. To date, the NCF has not been applied to investigate decision-making in the high-risk setting. Our objective was to use the NCF to describe the risk management beliefs of high-risk women prior to initial consultation. The relative importance of BC fear, perceived susceptibility to BC and necessity-concerns beliefs in predicting prevention intentions was also examined.

Methods A survey was sent to patients prior to their first risk consultation. BC fear was assessed with Champion BC Fear Scale and perceived susceptibility was measured by asking women to rate their likelihood of developing BC (0 =definitely will not get it to 100=definitely will get it). For each of screening, lifestyle modifications, pharmacoprevention (PP) and prophylactic surgery (PS), women rated (1=strongly disagree to 5=strongly agree) their need for the option (e.g., my health in the future will depend on this option, this option will protect me from becoming worse), and its negative consequences (e.g. I worry about the long-term effects of this option, this option will disrupt my life). Intentions were assessed by asking how strongly (1=definitely not to 5=Definitely Yes) they intended to adopt each option. The planned sample size is 100 women and recruitment is on-going. We report data from 44 women who have completed the questionnaire.

Results: The majority intended to adopt screening (92%) and lifestyle (91%) compared to PP (23%) or PS (18%). Screening and lifestyle were associated with stronger intentions, higher perceived need, and lower concerns than PP and PS (all t-tests, p &lt;0.0001). Hierarchical regression analyses revealed that perceived need predicted intentions for each option (all ps &lt; 0.005, except for screening, p &lt; .1) whereas concern beliefs were only correlated with PP intentions (β=-.398, p &lt; .005). Fear of BC was related to PP intentions (β=.401, p &lt; .005) and to intentions to remain smoke-free (β=-.341, p &lt; .05). Perceived susceptibility did not contribute to intentions.

Conclusions Our preliminary findings are promising and suggest that the NCF is useful for understanding decision-making in the high-risk setting. The findings emphasize the importance of necessity beliefs in BC risk management decisions. For the group as whole, across each risk management option, the strongest predictor of intentions was a women's perception of her personal need for the option. Concerns about negative effects and BC fear played only a minor role and perceived susceptibility did not predict intentions. These observations stress the importance of making screening or prevention recommendations hand in hand with the individual beliefs and concerns.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-08-04.

Use of an evidence-based shift report tool to improve nurses' communication

Using steps in the Iowa Model of Evidence-Based Practice, nursing staff developed and piloted a standardized shift report tool on one medical-surgical unit in a large tertiary care hospital. Pilot outcomes showed shift reports with decreased frequency of missed information, fewer delays in shift starting time, and less use of overtime.

Lower extremity kinematics in runners with patellofemoral pain during a prolonged run

PURPOSE

Investigate lower extremity kinematics in runners with patellofemoral pain (PFP) syndrome during a prolonged run.

METHODS

For this study, 20 runners with PFP and 20 uninjured controls performed a prolonged run on a treadmill at a self-selected pace. The run ended based on HR, perceived exertion, or level of knee pain. Kinematic data were analyzed at the beginning and at the end of the run.

RESULTS

The PFP group demonstrated less peak knee flexion, peak hip adduction, eversion excursion, peak knee flexion velocity, peak hip adduction velocity, and peak hip internal rotation velocity compared with controls. A significant main effect for time indicated that increases in most kinematic variables occurred at the end of the run. Interestingly, five runners with PFP displayed atypical motions of knee valgus and eight displayed hip abduction during the first half of stance.

CONCLUSIONS

The PFP group as a whole displayed less overall motion compared with controls. This may be indicative of a strategy aimed at limiting lower extremity movement to reduce pain. However, increases in joint motion occurred at the end of the run where pain levels were greatest. Three distinct PFP subgroups were noted, and each demonstrated unique kinematic mechanisms that may be associated with PFP. In the knee valgus subgroup, increased knee valgus and decreased peak motions were noted in other joints. In the hip abduction subgroup, less knee flexion and motion overall was noted. In the subgroup that displayed typical first half patterns (knee and hip adduction), increased hip internal rotation and decreased knee internal rotation were observed. These results suggest that several different kinematic mechanisms related to PFP may exist.

Improving between-day kinematic reliability using a marker placement device

3D motion analysis is commonly used to measure clinical outcomes, involving repeated measures over time. However, the day-to-day reliability of these measurements has been questioned and few attempts have been made to improve this reliability. Our purpose was to determine if a marker placement device (MPD) could improve day-to-day kinematic reliability as compared to manual marker placement. Ten healthy runners participated. Day-to-day comparisons of peak angles were made between manual marker placement and the use of an MPD. Reliability of each method was determined with intraclass correlation coefficients (ICC) and standard errors of measurement (SEM). The ICC and SEM values improved with the MPD. With the MPD, 7 out of 9 ICC values were >0.9 compared to only 3 when using manual marker placement. Additionally, the largest reduction in SEM values was in the transverse plane. Use of the MPD increases the power to detect smaller differences in studies of where gait is assessed over time.

Epidemiology of influenza-associated hospitalization in adults, Toronto, 2007/8

The purpose of this investigation was to identify when diagnostic testing and empirical antiviral therapy should be considered for adult patients requiring hospitalization during influenza seasons. During the 2007/8 influenza season, six acute care hospitals in the Greater Toronto Area participated in active surveillance for laboratory-confirmed influenza requiring hospitalization. Nasopharyngeal (NP) swabs were obtained from patients presenting with acute respiratory or cardiac illness, or with febrile illness without clear non-respiratory etiology. Predictors of influenza were analyzed by multivariable logistic regression analysis and likelihoods of influenza infection in various patient groups were calculated. Two hundred and eighty of 3,917 patients were found to have influenza. Thirty-five percent of patients with influenza presented with a triage temperature >or=38.0 degrees C, 80% had respiratory symptoms in the emergency department, and 76% were >or=65 years old. Multivariable analysis revealed a triage temperature >or=38.0 degrees C (odds ratio [OR] 3.1; 95% confidence interval [CI] 2.3-4.1), the presence of respiratory symptoms (OR 1.7; 95% CI 1.2-2.4), admission diagnosis of respiratory infection (OR 1.8; 95% CI 1.3-2.4), admission diagnosis of exacerbation of chronic obstructive pulmonary disease (COPD)/asthma or respiratory failure (OR 2.3; 95% CI 1.6-3.4), and admission in peak influenza weeks (OR 4.2; 95% CI 3.1-5.7) as independent predictors of influenza. The likelihood of influenza exceeded 15% in patients with respiratory infection or exacerbation of COPD/asthma if the triage temperature was >or=38.0 degrees C or if they were admitted in the peak weeks during the influenza season. During influenza season, diagnostic testing and empiric antiviral therapy should be considered in patients requiring hospitalization if respiratory infection or exacerbation of COPD/asthma are suspected and if either the triage temperature is >or=38.0 degrees C or admission is during the weeks of peak influenza activity.

The effect of real-time gait retraining on hip kinematics, pain and function in subjects with patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome (PFPS) is the most common overuse injury in runners. Recent research suggests that hip mechanics play a role in the development of this syndrome. Currently, there are no treatments that directly address the atypical mechanics associated with this injury.

OBJECTIVE

The purpose of this study was to determine whether gait retraining using real-time feedback improves hip mechanics and reduces pain in subjects with PFPS.

METHODS

Ten runners with PFPS participated in this study. Real-time kinematic feedback of hip adduction (HADD) during stance was provided to the subjects as they ran on a treadmill. Subjects completed a total of eight training sessions. Feedback was gradually removed over the last four sessions. Variables of interest included peak HADD, hip internal rotation (HIR), contralateral pelvic drop, as well as pain on a verbal analogue scale and the lower-extremity function index. We also assessed HADD, HIR and contralateral pelvic drop during a single leg squat. Comparisons of variables of interest were made between the initial, final and 1-month follow-up visit.

RESULTS

Following the gait retraining, there was a significant reduction in HADD and contralateral pelvic drop while running. Although not statistically significant, HIR decreased by 23% following gait retraining. The 18% reduction in HADD during a single leg squat was very close to significant. There were also significant improvements in pain and function. Subjects were able to maintain their improvements in running mechanics, pain and function at a 1-month follow-up. An unexpected benefit of the retraining was an 18% and 20% reduction in instantaneous and average vertical load rates, respectively.

CONCLUSIONS

Gait retraining in individuals with PFPS resulted in a significant improvement of hip mechanics that was associated with a reduction in pain and improvements in function. These results suggest that interventions for PFPS should focus on addressing the underlying mechanics associated with this injury. The reduction in vertical load rates may be protective for the knee and reduce the risk for other running-related injuries.