Roy T.H. Cheung

Landing Pattern Modification to Improve Patellofemoral Pain in Runners: A Case Series

STUDY DESIGN Case series. BACKGROUND Patellofemoral pain is a common overuse injury in runners. Recent findings suggest that patellofemoral pain is related to high-impact loading associated with a rearfoot strike pattern. This case series describes the potential training effects of a landing pattern modification program to manage patellofemoral pain in runners. CASE DESCRIPTION Three female runners with unilateral patellofemoral pain who initially presented with a rearfoot strike pattern underwent 8 sessions of landing pattern modification program using real-time audio feedback from a force sensor placed within the shoe. Ground reaction forces during running were assessed with an instrumented treadmill. Patellofemoral pain symptoms were assessed using 2 validated questionnaires. Finally, running performance was measured by self-reported best time to complete a 10-km run in the previous month. The runners were assessed before, immediately after, and 3 months following training. OUTCOMES The landing pattern of runners was successfully changed from a rearfoot to a nonrearfoot strike pattern after training. This new pattern was maintained 3 months after the program. The vertical impact peak and rates of loading were shown to be reduced. Likewise, the symptoms related to patellofemoral pain and associated functional limitations were improved. However, only 1 of the participants reported improved running performance after the training. DISCUSSION This case series provided preliminary data to support further investigation of interventions leading to landing pattern modification in runners with patellofemoral pain. LEVEL OF EVIDENCE Therapy, level 4.

Association of Footwear with Patellofemoral Pain Syndrome in Runners

Patellofemoral pain syndrome (PFPS) is a common knee problem with a diverse aetiology. One of the clinically well accepted risk factors is malalignment of the lower extremities, including excessive foot pronation, tibial and femoral rotations. A feature of footwear technology entitled ‘motion control’ aims to reduce excessive movements of the rearfoot during sports activities, and has been developed and used by runners. However, no studies have reported a causal relationship between footwear and PFPS. This review attempts to explore a possible link between the footwear and PFPS so as to shed light on whether proper selection of shoes may be an adjunct therapeutic consideration in the management of patients with PFPS.

H:Q Ratios and Bilateral Leg Strength in College Field and Court Sports Players

H:Q Ratios and Bilateral Leg Strength in College Field and Court Sports Players One of the key components in sports injury prevention is the identification of imbalances in leg muscle strength. However, different leg muscle characteristics may occur in large playing area (field) sports and small playing area (court) sports, which should be considered in regular injury prevention assessment. This study examined the isokinetic hamstrings-to-quadriceps (H:Q) ratio and bilateral leg strength balance in 40 male college (age: 23.4 ± 2.5 yrs) team sport players (field sport = 23, soccer players; court sport = 17, volleyball and basketball players). Five repetitions of maximal knee concentric flexion and concentric extension were performed on an isokinetic dynamometer at two speeds (slow: 60 °·s-1 and fast: 300°·s-1) with 3 minutes rest between tests. Both legs were measured in counterbalanced order with the dominant leg being determined as the leg used to kick a ball. The highest concentric peak torque values (Nm) of the hamstrings and quadriceps of each leg were analyzed after body mass normalization (Nm·kg-1). Court sport players showed significantly weaker dominant leg hamstrings muscles at both contraction speeds (P < 0.05). The H:Q ratio was significantly larger in field players in their dominant leg at 60°·s-1 (P < 0.001), and their non-dominant leg at 300°·s-1 (P < 0.001) respectively. Sport-specific leg muscle strength was evident in college players from field and court sports. These results suggest the need for different muscle strength training and rehabilitation protocols for college players according to the musculature requirements in their respective sports.

Efficacies of different external controls for excessive foot pronation: a meta-analysis

Objectives This meta-analysis investigated the efficacies of foot orthoses, motion control footwear and therapeutic adhesive taping in controlling foot pronation as compared with no-intervention conditions. Data sources Electronic searches on four electronic databases were performed and the reference lists of the screened articles were also scrutinised. Review methods Two reviewers screened the quasi-randomised or clinical controlled trials that examined the efficacy of the selected interventions in controlling calcaneal eversion. Heterogeneity and publication bias were assessed by I2 index and Eggers regression intercept, respectively. Trial quality was rated by the Physiotherapy Evidence Database scale. Results 29 studies were selected. The I2 indices revealed large heterogeneity which supported the use of a random effect model of meta-analysis. The Eggers regression intercepts suggested that publication bias of the included studies was marginally present in the motion control footwear and the therapeutic adhesive taping groups (p=0.06–0.07). All three interventions were effective in reducing calcaneal eversion (p<0.001) with therapeutic adhesive taping being most effective whereas Low-dye taping was less effective than the other taping techniques, such as high-dye and stirrups taping. Custom-made foot orthoses were more effective than prefabricated orthoses. Motion control footwear with heel flare or wedge design was less effective than those with dual midsole materials. Conclusions Foot orthoses, motion control footwear and therapeutic adhesive taping were able to control rearfoot eversion with therapeutic adhesive taping being the most effective. In the clinical practice, selection of an antipronation intervention should be based on patient characteristics, type of activity and personal preference.

Landing pattern and vertical loading rates during first attempt of barefoot running in habitual shod runners.

There is evidence supporting that habitual barefoot runners are able to disperse impact loading rates by landing pattern modification. Yet, case studies suggested that barefoot running may result in severe running injuries, such as metatarsal and calcaneal stress fractures. Injuries may be due to a difference in biomechanical response between habitual and novice barefoot runners. This study investigated the initial effects of barefoot running in habitual shod runners in terms of landing pattern modification and vertical loading rates. Thirty habitual shod runners (mean age 25.5±5.2years; 18 men; with a minimum running mileage of 30km per week for at least one year) ran on an instrumented treadmill at 10km/h shod and barefoot in a randomized order. Vertical average (VALR) and instantaneous loading rates (VILR) were obtained by established methods. Landing pattern was presented as a ratio between the number of footfalls with a heelstrike and the total step number. Twenty participants demonstrated an automatic transition to a non-heelstrike landing during barefoot running, whereas a mixed landing pattern was observed in 10 participants. Compared to shod running, both VALR and VILR were significantly reduced during barefoot running (p<.021). In the subgroup analysis, VALR for the shod condition was significantly higher than barefoot running, regardless of the landing pattern. VALR for the non-heelstrike pattern during barefoot running was significantly lower than participants with a mixed landing pattern. Conversely, we observed two participants who completely altered their landing patterns, presented high VALR and VILR values. Habitual shod runners presented lower loading rates during barefoot running but their landing pattern transitions were not uniform. Novice barefoot runners with a mixed landing pattern may sustain higher loading rates, compared with those who completely avoided heelstrike pattern. However, a complete landing pattern modification may not guarantee lower loading rates.

Influence of Different Footwear on Force of Landing During Running

Background and Purpose: Previous studies have demonstrated an increase in foot pronation with mileage in runners. Motion control footwear was designed to check excessive foot motions, but its clinical efficacy, especially in terms of pedographic analysis, has not been well reported. The purposes of this study were to investigate the changes in plantar force in people when running with motion control shoes and to compare pedographic measurements obtained in 2 footwear testing conditions (wearing motion control shoes and wearing neutral shoes) at the beginning and end of a 1.5-km running session. Subjects: Twenty-five recreational runners who had ≥6 degrees of foot pronation participated in the study. Methods: An insole sensor was used to register the plantar force of the subjects before and after running 1.5 km in different shoe conditions. Results: There was no change in the magnitude and distribution pattern of plantar force with the motion control shoes after the 1.5-km run. With the neutral shoes, however, there was an increase in mean peak force under the medial midfoot (364–418 N, 15% increase) and first metatarsal head (524–565 N, 8% increase) toward the end of the running bout. Discussion and Conclusion: The plantar force on the medial foot structures increased with mileage of running with neutral shoes but not with motion control shoes. This finding has implications for injury prevention with footwear selection for recreational runners who have more than 6 degrees of foot pronation.

Kinesiology tape does not facilitate muscle performance: A deceptive controlled trial

Kinesiology tape (KinTape) is a therapeutic tape without much understanding of its mechanism. KinTape claims to increase cutaneous stimulation, which facilitates motor unit firing, and consequently improves functional performance; however these, benefits could be due to placebo effects. This study investigated the true effects of KinTape by a deceptive, randomized, and controlled trial. Thirty healthy participants performed isokinetic testing of three taping conditions: true facilitative KinTape, sham KinTape, and no KinTape. The participants were blindfolded during the evaluation. Under the pretense of applying adhesive muscle sensors, KinTape was applied to their quadriceps in the first two conditions. Normalized peak torque, normalized total work, and time to peak torque were measured at two angular speeds (60°/s and 180°/s) and analyzed with one-way repeated measures ANOVA. Participants were successfully deceived and they were ignorant about KinTape. No significant differences were found between normalized peak torque, normalized total work, and time to peak torque at 60°/s or 180°/s (p = 0.31-0.99) between three taping conditions. The results showed that KinTape did not facilitate muscle performance in generating higher peak torque, yielding a greater total work, or inducing an earlier onset of peak torque. These findings suggest that previously reported muscle facilitatory effects using KinTape may be attributed to placebo effects.

Facilitatory and inhibitory effects of Kinesio tape: Fact or fad?

OBJECTIVES Kinesio tape (KT) is a commonly used intervention in sports. It claims to be able to alter the muscle activity, in terms of both facilitation and inhibition, by certain application methods. This study compared the neuromuscular activity of the wrist extensor muscles and maximal grip strength with facilitatory, inhibitory KT, and tapeless condition in healthy adults who were ignorant about KT. Potential placebo effects were eliminated by deception. DESIGN Randomized deceptive trial. METHODS 33 participants performed maximal grip assessment in a randomly assigned order of three taping conditions: true facilitatory KT, inhibitory KT, and no tape. The participants were blindfolded during the evaluation. Under the pretense of applying a series of adhesive muscle sensors, KT was applied to their wrist extensor muscles of the dominant forearm in the first two conditions. Within-subject comparisons of normalized root mean square of the wrist extensors electromyographic activity and maximal grip strength were conducted across three taping conditions. RESULTS 31 out of 33 enlisted participants were confirmed to be ignorant about KT. No significant differences were found in the maximum grip strength (p=0.394), electromyographic activity (p=0.276), and self-perceived performance (p=0.825) between facilitatory KT, inhibitory KT, and tapeless conditions. CONCLUSIONS Neither facilitatory nor inhibitory effects were observed between different application techniques of KT in healthy participants. Clinically, alternative method should be used for muscle activity modulation.

Chinese translation and validation of the Kujala scale for patients with patellofemoral pain

Purpose: This study translated and validated the Kujala scale, a well-documented questionnaire for patients with patellofemoral pain, into Chinese version. Method: Chinese Kujala scale was translated from the original English version following the recommendations of the International Society for Pharmacoeconomics and Outcomes Research. Sixty four Chinese reading patients who are diagnosed of patellofemoral pain were recruited from multiple hospitals and physiotherapy clinics. Psychometric property was evaluated in terms of test-retest reliability and internal consistency. Convergent validity was examined by Spearman rank correlation coefficient tests by comparing its score with the validated Chinese version of WOMAC Osteoarthritis Index and SF-36. Results: Chinese Kujala scale demonstrated excellent reliability (ICC = 0.968, p < 0.001). Cronbach’s α of individual questions and its overall value were above 0.7. Strong correlation was found between the Chinese Kujala scale and the WOMAC Osteoarthritis Index (rho = −0.708, p < 0.001). Fairly weak correlations were also found between Chinese Kujala scale with the “physical” (rho = 0.413–0.498, p < 0.001) and “energy vitality” (rho = 0.290, p = 0.02) domains of SF-36. However, the relationship between the “bodily pain” was not significant (rho = 0.136, p = 0.284). Conclusion: The Chinese translated version of Kujala scale is a reliable and valid instrument for assessing the patellofemoral pain associated functional disturbances among the patient cohort. Implications for Rehabilitation The Chinese translated version of Kujala scale is a reliable and valid instrument for assessing the functional disturbances associated with patellofemoral pain among the patient cohort. This instrument facilitates research among Chinese population and multinational studies.

Enforced bipedal downhill running induces Achilles tendinosis in rats.

Enforced downhill running has been reported to induce tendinosis in the rat supraspinatus tendon but similar exercise failed to induce Achilles tendinosis in this animal. Due to the presence of acromial arch in the shoulder, accessing the supraspinatus tendon with physical modalities is difficult; thus this model may not be suitable for studying the treatment for tendinosis. To develop a rat model for Achilles tendinosis, we tested 14 mature Sprague–Dawley rats by dividing them into 2 groups of 7 each. The experimental group was subjected to a daily enforced downhill bipedal running program by suspending their upper bodies so that they ran with their hind limbs on a treadmill for 1 hr/day for 8 weeks. The downward inclination was 20° and the speed was 17 m/min. The animals in the control group did not undergo any exercise. After 8 weeks, the Achilles tendons were harvested and subjected to histological and biomechanical analysis. Histological examination revealed tenocyte proliferation, change in tenocytes appearance, and collagen bundle disintegration in the running group. The biomechanical testing revealed significant decrease in stiffness (p = 0.002) and ultimate tensile strength (p = 0.016) in the running group than in the control group. Both the histological and biomechanical findings are suggestive of changes in the tendon of the running group that resembled the pathological changes of tendinosis in human. This new model of Achilles tendinosis in rat will be useful for studying the etiology and subsequent management strategies of this condition.