TEMPORAL PATTERN OF KINESIOLOGY TAPE EFFICACY ON HAMSTRING EXTENSIBILITY

Background

Kinesiology tape has been advocated as a means of improving muscle flexibility, a potential modifiable risk factor for injury, over time. The epidemiology and etiology of hamstring injuries in sport have been well documented.

Purpose

To compare the temporal pattern of efficacy of kinesiology tape and traditional stretching techniques on hamstring extensibility over a five day period.

Study Design

Controlled laboratory study.

Methods

Thirty recreationally active male participants (Mean ± SD: age 20.0 ± 1.55 years; height 179.3 ± 4.94 cm; mass 76.9 ± 7.57 kg) completed an active knee extension assessment (of the dominant leg) as a measure of hamstring extensibility. Three experimental interventions were applied in randomized order: Kinesiology tape (KT), static stretch (SS), proprioceptive neuromuscular facilitation (PNF). Measures were taken at baseline, +1min, + 30mins, + 3days and +5days days after each intervention. The temporal pattern of change in active knee extension was modelled as a range of regression polynomials for each intervention, quantified as the regression coefficient.

Results

Hamstring ROM with KT application at +3days was significantly greater than baseline (129.18 ± 15.46%, p = 0.01), SS (106.99 ± 9.84%, p = 0.03) and PNF (107.42 ± 136.13%, p = 0.03) interventions. The temporal pattern of changes in ROM for SS and PNF were best modelled by a negative linear function, although the strength of the correlation was weak in each case. In contrast, the KT data was optimised using a quadratic polynomial function (r² = 0.60), which yielded an optimum time of 2.76 days, eliciting a predicted ROM of 129.6% relative to baseline.

Conclusion

Each intervention displayed a unique temporal pattern of changes in active knee extension. SS was best suited to immediate improvements, and PNF to +30 minutes in hamstring extensibility, whereas kinesiology tape offered advantages over a longer duration, peaking at 2.76 days. These findings have implications for the choice of intervention, timing and duration to assist clinicians in both a sporting and clinical context.

Level of evidence

2c     

TEMPORAL EFFICACY OF KINESIOLOGY TAPE VS. TRADITIONAL STRETCHING METHODS ON HAMSTRING EXTENSIBILITY

Background

The epidemiology and aetiology of hamstring injuries in sport have been well documented. Kinesiology tape has been advocated as a means of improving muscle flexibility, with potential implications for injury prevention. Purpose: To compare the temporal pattern of efficacy of kinesiology tape and traditional stretching techniques on hamstring extensibility. Study Design: Controlled laboratory study. Methods: Thirty recreationally active male participants (Mean ± SD: age 21.0 ± 0.1 years; height 180 ± 6 cm; mass 79.4 ± 6.9 kg) completed an active knee extension assessment (of the dominant leg) as a measure of hamstring extensibility. Three experimental interventions of equal time duration were applied in randomized order: Kinesiology tape (KT), static stretch (SS), proprioceptive neuromuscular facilitation (PNF). Measures were taken at baseline, +1, +10 and +30 mins after each intervention. The temporal pattern of change in active knee extension (AKE) was modelled as a range of regression polynomials for each intervention, quantified as the regression coefficient. Results: With baseline scores not statistically different between groups, and baseline AKE set at 100%, PNF showed a significant improvement immediately post‐intervention (PNF₊₁ = 107.7 ± 8.2%, p = .01). Thereafter, only KT showed significant improvements in active knee extension (KT₊₁₀ = 106.0 ± 7.1%, p = .05; KT₊₃₀ = 106.9 ± 5.0%, p = .02). The temporal pattern of changes in active knee extension after intervention was best modelled as a positive quadratic for KT, with a predicted peak of 108.8% baseline score achieved at 24.2 mins. SS was best modelled as a negative linear function, and PNF as a negative logarithmic function, reflecting a rapid decrease in active knee extension after an immediate positive effect. Conclusion: Each intervention displayed a unique temporal pattern of changes in active knee extension. PNF was best suited to affect immediate improvements in hamstring extensibility, whereas kinesiology tape offered advantages over a longer duration. Clinical Relevance: The logistics of the sporting or clinical context will often dictate the delay between intervention and performance. Our findings have implications for the timing and choice of intervention aimed at increasing hamstring extensibility in relation to performance.

Level of Evidence

2c     

EFFECTS OF A MOVEMENT TRAINING PROGRAM ON HIP AND KNEE JOINT FRONTAL PLANE RUNNING MECHANICS

Background/Purpose:

Frontal plane running mechanics may contribute to the etiology or exacerbation of common running related injuries. Hip strengthening alone may not change frontal plane hip and knee joint running mechanics. The purpose of the current study was to evaluate whether a training program including visual, verbal, and tactile feedback affects hip and knee joint frontal plane running mechanics among females with evidence of altered weight bearing kinematics.

Methods:

The knee frontal plane projection angle of 69 apparently healthy females was determined during a single leg squat. The twenty females from this larger sample who exhibited the most acute frontal plane projection angle (medial knee position) during this activity were chosen to participate in this study (age = 20 ± 1.6 years, height = 167.9 ± 6.0 cm, mass = 63.2 ± 8.3 kg, Tegner Activity Rating mode = 7.0). Participants engaged in a 4‐week movement training program using guided practice during weight bearing exercises with visual, verbal, and tactile feedback regarding lower extremity alignment. Paired t‐tests were used to compare frontal plane knee and hip joint angles and moments before and after the training program.

Results:

After training, internal hip and knee abduction moments during running decreased by 23% (P=0.007) and 29% (P=0.033) respectively. Knee adduction and abduction excursion decreased by 2.1° (P = 0.050) and 2.7° (P=0.008) respectively, suggesting that less frontal plane movement of the knee occurred during running after training. Peak knee abduction angle decreased 1.8° after training (P=0.051) although this was not statistically significant. Contralateral peak pelvic drop, pelvic drop excursion, peak hip adduction angle, hip adduction excursion, and peak knee adduction angle were unchanged following training.

Conclusions:

A four week movement training program may reduce frontal plane hip and knee joint mechanics thought to contribute to the etiology and exacerbation of some running related injuries.

Level of Evidence:

Level 4     

THE EFFECT OF KINESIO? TAPE ON VERTICAL JUMP AND DYNAMIC POSTURAL CONTROL

Introduction and Background:

Ankle injuries are one of the most common injuries among physically active individuals. The role of prophylactic ankle taping and bracing has been studied extensively. Kinesio^® Tape (KT) is a somewhat new type of taping technique gaining popularity as both treatment and performance enhancement tool. However, there is limited research on the effect of KT on functional performance.

Purpose:

The purpose of this study was to determine whether the application of Kinesio Tex^® Tape had an effect on vertical jump and dynamic postural control in healthy young individuals.

Methods:

52 healthy subjects free of ankle or lower extremity problems (28 males and 24 females; age: 22.12±2.08 years; height: 170.77±8.69 cm; weight: 69.90±12.03 kg) participated in the study. Subjects were randomly assigned to either the experimental group (KT with tension) or the control group (KT without tension). Vertical jump was measured using the VertiMetric device and dynamic postural control was assessed using the Star Excursion Balance Test (SEBT) under three conditions: (1) without taping; (2) immediately after taping; (3) 24 hours after taping with the taping remaining in situ.

Results:

Three-way repeated measure ANOVA was conducted in order to identify differences between the experimental and the control group during the three conditions. Overall, there were no differences between groups in vertical jump maximum height, vertical jump average height, or the SEBT scores for the three time periods (pre-test, post-test, 24hrs-post-test). However, the main effect of KT was moderated by a significant gender interaction, resulting in a statistically significant effect of KT for the SEBT scores in the posterior-medial direction, F(1.72, 82.57) = 4.50, p = 0.018 and the medial direction, F(1.75, 83.81) = 4.27, p = 0.021. Follow-up analyses indicated that female subjects in the KT group had increased SEBT scores between three time periods when compared to the placebo group.

Discussion:

KT application on the ankle neither decreased nor increased vertical jump height in healthy non-injured young individuals, but did increase dynamic postural control in females for certain directions. Additional study is warranted using different measures of balance to further investigate the effect of KT on dynamic postural control.

Level of Evidence:

2b     

Associations between low back pain,urinary incontinence,and abdominal muscle recruitment as assessed via ultrasonography in the elderly

Background:

Low back pain (LBP) and urinary incontinence (UI) are highly prevalent among elderly individuals. In young adults, changes in trunk muscle recruitment, as assessed via ultrasound imaging, may be associated with lumbar spine stability.

Objective:

To assess the associations between LBP, UI, and the pattern of transversus abdominis (TrA), internal (IO), and external oblique (EO) muscle recruitment in the elderly as evaluated by ultrasound imaging.

Method:

Fifty-four elderly individuals (mean age: 72±5.2 years) who complained of LBP and/or UI as assessed by the McGill Pain Questionnaire, Incontinence Questionnaire-Short Form, and ultrasound imaging were included in the study. The statistical analysis comprised a multiple linear regression model, and a p-value <0.05 was considered significant.

Results:

The regression models for the TrA, IO, and EO muscle thickness levels explained 2.0% (R²=0.02; F=0.47; p=0.628), 10.6% (R²=0.106; F=3.03; p=0.057), and 10.1% (R²=0.101; F=2.70; p=0.077) of the variability, respectively. None of the regression models developed for the abdominal muscles exhibited statistical significance. A significant and negative association (p=0.018; β=-0.0343) was observed only between UI and IO recruitment.

Conclusion:

These results suggest that age-related factors may have interfered with the findings of the study, thus emphasizing the need to perform ultrasound imaging-based studies to measure abdominal muscle recruitment in the elderly.     

Effectiveness of Surface Electromyographic Biofeedback-Triggered Neuromuscular Electrical Stimulation on Knee Rehabilitation

Background

Neuromuscular electrical stimulation initiated by a surface electromyographic biofeedback threshold (sEMG-triggered NMES) has been studied in populations of patients with neurological problems, but has not been applied to orthopedic populations.

Objectives

The purpose of this single-blinded, randomized clinical trial was to investigate sEMG-triggered NMES on knee extension active range of motion (AROM), function, and torque in patients with post-operative arthroscopic knee surgery.

Methods

Twenty-five participants were randomly assigned to either: (1) sEMG-triggered NMES with exercise group, or (2) exercise-only comparison group. Participants received outpatient physical therapy treatment 2 to 3 times a week for 12 visits. Knee AROM and function determined by the lower extremity functional scale (LEFS) were collected at the first, sixth, and twelfth visits. Peak isometric extensor torque was assessed using an electromechanical dynamometer at 3 months post surgery. Two analysis of variance tests with repeated measures were used to analyze knee AROM and LEFS data. An independent samples t-test was used to analyze the peak torque index (%) of the involved extremity compared to the uninvolved.

Results

A significant difference in AROM was found between groups. No significant difference was found between groups in the LEFS, nor in the peak isometric extensor torque. A 72.5% strength deficit was found compared to the uninvolved extremity.

Conclusion

Using sEMG-triggered NMES intervention improved extension AROM but did not improve function or torque.     

THE IMMEDIATE AND LONG-TERM EFFECTS OF KINESIOTAPE? ON BALANCE AND FUNCTIONAL PERFORMANCE

Background

The application of Kinesio Tex® tape (KT) results, in theory, in the improvement of muscle contractibility by supporting weakened muscles. The effect of KT on muscle strength has been investigated by numerous researchers who have theorized that KT facilitates an immediate increase in muscle strength by generating a concentric pull on the fascia. The effect of KT on balance and functional performance has been controversial because of the inconsistencies of tension and direction of pull required during application of KT and whether its use on healthy individuals provides therapeutic benefits.

Hypotheses/Purpose

The purpose of the present study was to investigate the immediate and long-term effects of the prescribed application (for facilitation) of KT when applied to the dominant lower extremity of healthy individuals. The hypothesis was that balance and functional performance would improve with the prescribed application of KT versus the sham application.

Study Design

Pretest-posttest repeated measures control group design.

Methods

Seventeen healthy subjects (9 males; 8 females) ranging from 18-35 years of age (mean age 23.3 ± 0.72), volunteered to participate in this study. KT was applied to the gastrocnemius of the participant''s dominant leg using a prescribed application to facilitate muscle performance for the experimental group versus a sham application for the control group. The Biodex Balance System and four hop tests were utilized to assess balance, proprioception, and functional performance beginning on the first day including pre- and immediately post-KT application measurements. Subsequent measurements were performed 24, 72, and 120 hours after tape application. Repeated measures ANOVA''s were performed for each individual dependent variable.

Results

There were no significant differences for main and interaction effects between KT and sham groups for the balance and four hop tests.

Conclusion

The results of the present study did not indicate any significant differences in balance and functional performance when KT was applied to the gastrocnemius muscle of the lower extremity.

Level of evidence

Level 1- Randomized Clinical Trial     

Skinfold thickness affects the isometric knee extension torque evoked by Neuromuscular Electrical Stimulation

BACKGROUND:

Subcutaneous adipose tissue may influence the transmission of electrical stimuli through to the skin, thus affecting both evoked torque and comfort perception associated with neuromuscular electrical stimulation (NMES). This could seriously affect the effectiveness of NMES for either rehabilitation or sports purposes.

OBJECTIVE:

To investigate the effects of skinfold thickness (SFT) on maximal NMES current intensity, NMES-evoked torque, and NMES-induced discomfort.

METHOD:

First, we compared NMES current intensity, NMES-induced discomfort, and NMES-evoked torque between two subgroups of subjects with thicker (n=10; 20.7 mm) vs. thinner (n=10; 29.4 mm) SFT. Second, we correlated SFT to NMES current intensity, NMES-induced discomfort, and NMES-evoked knee extension torque in 20 healthy women. The NMES-evoked torque was normalized to the maximal voluntary contraction (MVC) torque. The discomfort induced by NMES was assessed with a visual analog scale (VAS).

RESULTS:

NMES-evoked torque was 27.5% lower in subjects with thicker SFT (p=0.01) while maximal current intensity was 24.2% lower in subjects with thinner SFT (p=0.01). A positive correlation was found between current intensity and SFT (r=0.540, p=0.017). A negative correlation was found between NMES-evoked torque and SFT (r=-0.563, p=0.012). No significant correlation was observed between discomfort scores and SFT (r_s=0.15, p=0.53).

CONCLUSION:

These results suggest that the amount of subcutaneous adipose tissue (as reflected by skinfold thickness) affected NMES current intensity and NMES-evoked torque, but had no effect on discomfort perception. Our findings may help physical therapists to better understand the impact of SFT on NMES and to design more rational stimulation strategies.     

LOWER EXTREMITY KINEMATICS IN RUNNING ATHLETES WITH AND WITHOUT A HISTORY OF MEDIAL SHIN PAIN

Purpose/Background:

Medial shin pain (MSP) is a common complaint that may stop an athlete from running. No previous study has identified deficits in pelvic, hip or knee motion as potential contributing factors to MSP. The purpose of this study was to investigate the differences in kinematics during running between uninjured athletes and those with MSP. Secondary analyses investigated differences in limbs between groups and differences between sexes.

Methods:

This case-control study investigated fourteen runners aged 18–40 years old with a history of unilateral MSP and fourteen runner controls. Three dimensional lower quarter kinematics were captured as runners ran on a treadmill. Specifically, peak hip internal rotation (IR), frontal plane pelvic tilt (PT) excursion, and knee flexion were examined.

Results:

Groups were similar in age, mass, height, and training mileage. Subjects with a history of MSP demonstrated significantly greater frontal plane PT (P = 0.002, Effect size = 0.55) and peak hip IR (P = 0.004, Effect size = 0.51); and less knee flexion (P = 0.02, Effect size = 0.46) than the control group. No significant difference was found in kinematics of the MSP group during their involved side stance phase as compared to their non-involved side.

Conclusions:

Runners with MSP displayed greater PT excursion, peak hip IR, and decreased knee flexion while running as compared to a control group. These results should help guide treatment for the running athlete that experiences MSP.

Level of Evidence:

3b     

Intraoperative experiments show relevance of inter-antagonistic mechanical interaction for spastic muscle's contribution to joint movement disorder

Background

Recent intra-operative knee angle–muscle force data showed no abnormal muscular mechanics (i.e., a narrow joint range of muscle force exertion and peak muscle force availability at flexed joint positions), if the spastic gracilis muscle was stimulated alone. This can limit inter-muscular mechanical interactions, which have been shown to affect muscular mechanics substantially. We aimed at testing the hypothesis that the knee angle–muscle force curves of the spastic gracilis muscle activated simultaneously with a knee extensor are representative of joint movement disorder.

Methods

Experiments were performed during remedial surgery of spastic cerebral palsy patients (n = 6, 10 limbs tested). Condition-I: muscle forces were measured in flexed knee positions (120° and 90°) after activating the gracilis exclusively. Condition-II: knee angle–muscle force data were measured from 120° to full extension after activating the vastus medialis, simultaneously.

Findings

Condition-II vs. I: Inter-antagonistic interaction did not consistently cause a gracilis force increase. Condition-II: Peak muscle force = mean 47.92 N (SD 22.08 N). Seven limbs showed availability of high muscle force in flexed knee positions (with minimally 84.8% of peak force at 120°). Knee angle–muscle force curves of four of them showed a local minimum followed by an increasing force (explained by an increasing passive force, indicating muscle lengths unfavorable for active force exertion). High active gracilis forces measured at flexed knee positions and narrow operational joint range of force exertion do indicate abnormality. The remainder of the limbs showed no such abnormality.

Interpretation

Our hypothesis is confirmed for most, but not all limbs tested. Therefore, tested inter-antagonistic mechanical interaction can certainly, but not exclusively be a factor for abnormal mechanics of the spastic muscle.     

CLINICAL OBSERVATION AND ANALYSIS OF MOVEMENT QUALITY DURING PERFORMANCE ON THE STAR EXCURSION BALANCE TEST

Study Design:

Observational

Background:

The Star Excursion Balance Test (SEBT) is used to evaluate dynamic postural control and screen for injury risk. No prior studies have investigated whether the quality of movement during the SEBT has clinical value and can adequately predict injury.

Purpose:

To develop a visual assessment tool and evaluate the relationship between movement quality and SEBT outcomes.

Methods:

One hundred healthy subjects were included. Baseline demographic, limb length, and individual SEBT performance data were collected. SEBT outcomes were obtained and used to classify individuals as at‐risk or not at‐risk. At‐risk individuals demonstrated anterior right/left reach distance difference greater than 4 cm, and/or normalized composite reach distance less than 89.6% for males or 94% for females. Three independent reviewers, blinded to SEBT outcomes, assessed the anterior reach test on videotape. Reviewers underwent training on a scoring system to assess movement quality at the trunk, pelvis, and knee. The total score of movement faults was used to determine interrater reliability and calculate sensitivity and specificity, in addition to positive and negative predictive values of SEBT outcome.

Results:

Seventy‐one subjects were classified as at risk. Interrater reliability of movement scoring was poor‐moderate for the trunk and pelvis (κ=0.18‐0.43), and moderate for the knee (κ=0.5‐0.6). Rater agreement for total movement score was fair‐moderate (W=0.64‐0.73). Rater assessment of aberrant movement was not predictive of SEBT performance. However, subjects deemed at risk had fewer movement faults per rater assessment. Raters displayed moderately strong specificity (0.59‐0.82) and poor sensitivity (0.14‐0.39) in knee assessment to detect at risk performance on the SEBT.

Conclusion:

Clinical observation of knee movement demonstrated acceptable interrater reliability and moderately strong specificity to detect at‐risk SEBT outcome. Total movement score across all regions demonstrated fair‐moderate agreement. Subjects who were at risk tended to have fewer movement faults.

Level of evidence:

3     

THE IMPACT OF SAGITTAL PLANE HIP POSITION ON ISOMETRIC FORCE OF HIP EXTERNAL ROTATOR AND INTERNAL ROTATOR MUSCLES IN HEALTHY YOUNG ADULTS

Purpose/Background:

Hip external rotator (ER) and internal rotator (IR) muscle weakness is theorized to be associated with lower extremity injury in athletes including knee ligament tears and patellofemoral pain. Previous studies investigating hip musculature strength have utilized various sagittal plane hip positions for testing. The relationship between results at these different positions is unknown.

Methods:

Eighty healthy, pain‐free young adults participated in the study: 40 female, mean age 22.90 (± 2.32) years, and 40 male, mean age 23.50 (± 2.15) years. Peak isometric torque of bilateral hip ER and IR were tested at 90° and 0° of hip flexion with an instrumented dynamometer. Peak muscle forces were calculated. Peak forces were normalized by body mass. Mean normalized force was calculated for dominant and non‐dominant limbs for ER and IR in both positions. Male and female data were analyzed separately with paired t‐tests (2‐tailed). Reference values for average muscle force and torque were calculated for dominant and non‐dominant limbs for both hip positions.

Results:

Hip IR normalized peak force was greater at 90° compared to 0° flexion position bilaterally in both genders (p < .01). Hip ER normalized peak force was greater at 90° compared to 0° flexion in dominant limbs of both genders and in non‐dominant limbs of males (p < .01). Non‐dominant hip ER normalized force in females was greater at 90° versus 0° flexion; however, it was not significant (p = .092). Post hoc analysis of normalized average force (average over 5‐second contraction) yielded similar results.

Conclusion:

Clinicians and researchers should use consistent positioning for testing of hip ER and IR strength. This will improve certainty of determining if a patient’s strength has changed or if differences between groups are present. Reference values reported will be useful in order to determine if weakness is present and to set goals, particularly in cases of bilateral involvement.

Level of Evidence:

2b     

NOT ALL SINGLE LEG SQUATS ARE EQUAL: A BIOMECHANICAL COMPARISON OF THREE VARIATIONS

Background

The single leg squat (SLS) is a functional task used by practitioners to evaluate and treat multiple pathologies of the lower extremity. Variations of the SLS may have different neuromuscular and biomechanical demands. The effect of altering the non-stance leg position during the SLS on trunk, pelvic, and lower extremity mechanics has not been reported.

Purpose

The purpose of this study was to compare trunk, pelvic, hip, knee, and ankle kinematics and hip, knee, and ankle kinetics of three variations of the SLS using different non-stance leg positions: SLS-Front, SLS-Middle, and SLS-Back.

Methods

Sixteen healthy women performed the three SLS tasks while data were collected using a motion capture system and force plates. Joint mechanics in the sagittal, frontal, and transverse planes were compared for the SLS tasks using a separate repeated-measures analysis of variance (ANOVA) for each variable at two analysis points: peak knee flexion (PKF) and 60 ° of knee flexion (60KF).

Results

Different non-stance leg positions during the SLS resulted in distinct movement patterns and moments at the trunk, pelvis, and lower extremity. At PKF, SLS-Back exhibited the greatest kinematic differences (p < 0.05) from SLS-Front and SLS-Middle with greater ipsilateral trunk flexion, pelvic anterior tilt and drop, hip flexion and adduction, and external rotation as well as less knee flexion and abduction. SLS-Back also showed the greatest kinetic differences (p < 0.05) from SLS-Front and SLS-Middle with greater hip external rotator moment and knee extensor moment as well as less hip extensor moment and knee adductor moment at PKF. At 60KF, the findings were similar except at the knee.

Conclusion

The mechanics of the trunk, pelvis, and lower extremity during the SLS were affected by the position of the non-stance leg in healthy females. Practitioners can use these findings to distinguish between SLS variations and to select the appropriate SLS for assessment and rehabilitation.

Level of Evidence

3     

CLINICAL EFFECTIVENESS OF KINESIOLOGICAL TAPING ON PAIN AND PAIN‐FREE SHOULDER RANGE OF MOTION IN PATIENTS WITH SHOULDER IMPINGEMENT SYNDROME: A RANDOMIZED,DOUBLE BLINDED,PLACEBO‐CONTROLLED TRIAL

Background:

Kinesiological taping (KT) is commonly used to improve symptoms associated with musculoskeletal disorders. However, review of the literature revealed minimal evidence to support the use of KT in treatment of shoulder disorders and controversy exists regarding the effect of KT in patients with shoulder impingement syndrome (SIS).

Objective:

The purpose of this study was to investigate the effect of KT on pain intensity during movement, pain experienced during the night (nocturnal pain), and pain‐free shoulder range of motion (ROM) immediately after taping, after three days and after one week, in patients with SIS.

Design:

Randomized, Double blinded, Placebo‐controlled design.

Participants:

A total of 30 patients with SIS participated in this study. Patients were assigned randomly to a control (N = 15) and an experimental group (N = 15).

Methods:

The patients in the experimental group received a standardized therapeutic KT. The standardized, placebo neutral KT was applied for control group. KT was applied two times with a three day interval, remaining on during the 3 day interval. Both groups followed the same procedures. Pain‐free active ROM during shoulder abduction, flexion, and elevation in the scapular plane was measured. Visual analogue scale (VAS) for pain intensity during movement or nocturnal pain and was assessed at baseline, immediately after KT, after three days, and one week after KT.

Results:

The result of repeated measures ANOVA showed a significant change in pain level during movement, nocturnal pain, and pain‐free ROM (p = 0.000) after KT in the experimental group. In the ANCOVA, controlling for pre‐test scores, change in pain level at movement (p = 0.009) and nocturnal pain (p = 0.04) immediately after KT was significantly greater in the experimental group than in control group. There was no significant difference in ROM measures (p > 0.05) between groups immediately after KT. No significant differences were found between the two groups in the after one week measurements of pain intensity and shoulder ROM.

Conclusion:

The KT produces an immediate improvement in the pain intensity at movement and nocturnal pain in patients with SIS.

Level of Evidence:

1     

Peak Biomechanical Variables During Bilateral Drop Landings: Comparisons Between Sex (Female/Male) and Fatigue (Pre-Fatigue/Post-Fatigue)

Background

Although anterior cruciate ligament (ACL) sprains usually occur during the initial phase of the landing cycle (less than 40° knee flexion), the literature has focused on peak values of knee angles, vertical ground reaction force (VGRF), and muscle activity even though it is unclear what occurs during the initial phase of landing.

Objectives

The objectives of this study were to determine the effects of sex (male and female) and fatigue (prefatigue/post-fatigue) on knee flexion angles at the occurrence of peak values of biomechanical variables [knee valgus angle, VGRF, and normalized electromyographic amplitude (NEMG) of the quadriceps and hamstring muscles] during a bilateral drop landing task.

Methods

Knee valgus angle, VGRF, and NEMG of the quadricep and hamstring muscles were collected during bilateral drop landings for twenty-nine recreational athletes before and after a fatigue protocol.

Results

Peak values of knee valgus, VGRF, and NEMG of medial and lateral hamstring muscles occurred during the late phase of the landing cycle (>40° of knee flexion). Females in the post-fatigue condition exhibited peak VGRF at significantly less knee flexion than in the pre-fatigue condition. Males in the post-fatigue condition exhibited peak lateral hamstring muscles NEMG at significantly higher knee flexion than in the pre-fatigue condition.

Discussion and Conclusion

Peak values of biomechanical variables that have been previously linked to ACL injury did not occur during the initial phase of landing when ACL injuries occur. No biomechanical variables peaked during the initial phase of landing; therefore, peak values may not be an optimal indicator of the biomechanical factors leading to ACL injury during landing tasks.     

STRENGTH & FUNCTIONAL ASSESSMENT OF HEALTHY HIGH SCHOOL FOOTBALL PLAYERS: ANALYSIS OF SKILLED AND NON‐SKILLED POSITIONS

Background/Purpose

Identifying an athlete''s functional capacity is an important consideration in determining when to allow an athlete to return to competition following injury. Establishing normative data for lower extremity functional assessment is valuable for comparison when making decisions regarding the high school athlete returning to play after injury. Therefore, the purpose of this study was to compare functional performance and strength between American high school football players of both skilled and non‐skilled positions.

Methods

Forty‐nine high school football players (30 skilled; 19 non‐skilled) completed a single‐session of testing consisting of a Figure of 8 test (F‐8), single‐leg vertical jump (SLVJ), single‐leg broad jump (SLBJ), and isokinetic knee strength assessment. Pearson correlation coefficients were used to determine the relationships between the results of functional testing and isokinetic strength measures. Paired t‐tests were used to determine the differences in functional performance and isokinetic muscle strength between skilled and non‐skilled athletes.

Results

Knee extension peak torque/body weight (BW) was moderately correlated (p < .01) with SLBJ (r = .54‐.61), SLVJ (r = .39‐.48), and F‐8 run times (r = ‐.50) for all athletes. Similar relationships were observed between knee flexion peak torque/BW and SLBJ (r = .48‐.49), SLVJ (r = .28‐.46), and the F‐8 run times (r = .41‐.52) for all subjects. No differences were observed between groups when examining raw peak torque values for knee flexion and extension (p > .05), however, skilled players did demonstrate greater peak torque/BW ratios (p < .05) for both knee extension and knee flexion at 60 and 240 degrees/sec. Skilled players also displayed faster F‐8 times (9.4 sec ± .3; p < .01) and greater SLBJ (p < .05) on both the dominant (81.0 in ± 9.3) and non‐dominant (83.0 in ± 7.6) limbs (p < .01) when compared to non‐skilled players.

Conclusions

Overall, skilled football players displayed greater peak torque/BW ratios and functional performance when compared to non‐skilled players. Furthermore, isokinetic peak torque/BW appears to be related to functional performance. This relationship is affected by position, with skilled players showing a stronger association. Limb dominance did not influence these functional and strength metrics. It is recommended that clinicians and coaches consider the positional differences in strength and functional performance when managing patients and athletes.

Level of Evidence

4 – Cross‐sectional Case Series     

Learning spinal manipulation: a comparison of two teaching models

Purpose:

The goal of the present study was to quantify the high-velocity, low-amplitude spinal manipulation biomechanical parameters in two cohorts of students from different teaching institutions. The first cohort of students was taught chiropractic techniques in a patient–doctor positioning practice setting, while the second cohort of students was taught in a “complete practice” manipulation setting, thus performing spinal manipulation skills on fellow student colleagues. It was hypothesized that the students exposed to complete practice would perform the standardized spinal manipulation with better biomechanical parameters.

Methods:

Participants (n = 88) were students enrolled in two distinct chiropractic programs. Thoracic spine manipulation skills were assessed using an instrumented manikin, which allowed the measurement of applied force. Dependent variables included peak force, time to peak force, rate of force production, peak force variability, and global coordination.

Results:

The results revealed that students exposed to complete practice demonstrated lower time to peak force values, higher peak force, and a steeper rate of force production compared with students in the patient–doctor positioning scenario. A significant group by gender interaction was also noted for the time to peak force and rate of force production variables.

Conclusion:

The results of the present study confirm the importance of chiropractic technique curriculum and perhaps gender in spinal manipulation skill learning. It also stresses the importance of integrating spinal manipulation skills practice early in training to maximize the number and the quality of significant learner–instructor interactions.     

Influence of aging on isometric muscle strength,fat-free mass and electromyographic signal power of the upper and lower limbs in women

Background

Aging is a multifactorial process that leads to changes in the quantity and quality of skeletal muscle and contributes to decreased levels of muscle strength.

Objective

This study sought to investigate whether the isometric muscle strength, fat-free mass (FFM) and power of the electromyographic (EMG) signal of the upper and lower limbs of women are similarly affected by aging.

Method

The sample consisted of 63 women, who were subdivided into three groups (young (YO) n=33, 24.7±3.5 years; middle age (MA) n=15, 58.6±4.2 years; and older adults (OA). n=15, 72.0±4.2 years). Isometric strength was recorded simultaneously with the capture of the electrical activity of the flexor muscles of the fingers and the vastus lateralis during handgrip and knee extension tests, respectively. FFM was assessed using dual-energy X-ray absorptiometry.

Results

The handgrip strength measurements were similar among groups (p=0.523), whereas the FFM of the upper limbs was lower in group OA compared to group YO (p=0.108). The RMSn values of the hand flexors were similar among groups (p=0.754). However, the strength of the knee extensors, the FFM of the lower limbs and the RMSn values of the vastus lateralis were lower in groups MA (p=0.014, p=0.006 and p=0.013, respectively) and OA (p=0.000, p=0.000 and p<0.000, respectively) compared to group YO.

Conclusions

The results of this study demonstrate that changes in isometric muscle strength in MLG and electromyographic activity of the lower limbs are more pronounced with the aging process of the upper limb.     

Relationships among the Y balance test,Berg Balance Scale,and lower limb strength in middle-aged and older females

Background:

Older females have less dynamic postural control and muscle strength than do middle-aged females. Aging-related strength losses may limit balancing performance.

Objective:

The purpose of this study was to investigate the ability of the Y Balance Test (YBT) and lower limb strength to discriminate between females in 2 age groups, the relationship between YBT distance and the Berg Balance Scale (BBS), and the degree to which performance on YBT distance is related to lower limb strength in middle-aged and older females.

Method:

The 40 healthy, independently active females were divided into 2 groups: older and middle-aged. The participants underwent measurements of YBT distance using the YBT, maximal muscular strength of the lower limbs using a handheld dynamometer, and the BBS.

Results:

The YBT distance in 3 directions and lower limb muscle strength for both lower limbs were significantly lower in the older adults than in the middle-aged group. A moderate correlation but insignificant correlation was found between the YBT composite distance and the BBS score. In the older females, YBT distance was significantly positively correlated with strength of the knee flexor and hip abductor. In the middle-aged group, YBT distance was significantly positively correlated with strength of the knee flexor and hip extensor.

Conclusions:

Performance on the YBT was influenced by the strength of lower limb. We suggested that YBT can be used to alternative as a measurement of dynamic balance. Proper training programs for older people could include not only strengthening exercises but also YBT performance to improve balance.     

ASSOCIATIONS BETWEEN KNEE EXTENSOR POWER AND FUNCTIONAL PERFORMANCE IN PATIENTS AFTER TOTAL KNEE ARTHROPLASTY AND NORMAL CONTROLS WITHOUT KNEE PAIN

Purpose/Background:

Deficits in functional abilities persist after total knee arthroplasty (TKA), while static measures of knee extensor strength (e.g. isometric contractions) are related to functional performance, little is known about the associations between functional ability and dynamic knee extensor strength (e.g. power). With the growing rate of these procedures, in a progressively younger and more active cohort, a better understanding of the functional importance of dynamic strength (muscle power) is needed. The purpose of this study was to examine the associations between functional performance and peak knee extensor power (isokinetic and isotonic measures) from patients after unilateral TKA.

Design:

Cross‐sectional, controlled laboratory study, with correlation and regression analyses.

Setting:

Institutional clinic and research laboratory.

Participants:

Patients 6 months after TKA (N=24, 12 men and women), most of whom were mildly to very active. A normal control group without knee pain (CON; N=22, 10 men and 12 women) was also assessed for comparison.

Main Outcome Measures:

Static and dynamic strength measures were assessed during normalized voluntary isometric contractions (NMVIC), isokinetic contractions at three velocities (60, 90, and 120 deg/s), and isotonic contractions against three body weight normalized resistances (20, 30 and 40% BW). Functional performance was assessed using the timed up‐and‐go (TUG), stair climbing test (SCT), and 6‐ minute walk (6MW). Analyses of the relationships between functional performance measures and peak knee extensor NMVIC and power were performed. Regression analyses predicting functional performance from power were also performed after controlling for NMVIC.

Results

Peak power across isokinetic velocities, isotonic resistances, and NMVICs were correlated with the functional performance measures for the TKA group. Unlike the TKA group, functional performance was not significantly associated with peak power across all isokinetic velocities and isotonic resistances (e.g no significant associations between peak isotonic power and 6MW distance). In the TKA group, inclusion of the isotonic power against 30% BW, after controlling for NMVIC, improved the predictability of all three functional performance tests; TUG (p= 0.022), SCT (p=0.006), and 6MW (p=0.001).

Conclusions

Measurements of knee extensor power may be a useful tool for clinicians when assessing and setting milestones during rehabilitation.

Level of Evidence:

Prospective cohort study, level II.