Short-term effects of kinesiology taping on static and dynamic balance in healthy subjects.

Background: As a therapeutic tool, kinesiology taping (KT) has become increasingly popular for musculoskeletal injuries utilized by physiotherapists. KT has been found to have effects on facilitating muscle strength by generating a concentric pull on the fascia. However, little is known about KT in the improvement of dynamic and static balance. This study aims to explore whether KT on the quadriceps muscle has any immediate effects on static and dynamic balance. Methodology: Twenty-seven healthy individuals (13 males and 14 females, aged 22 to 29) were recruited in a crossover study with two conditions: KT and no taping. KT was applied to the quadriceps muscle for the taping group, with the control receiving no taping. Pre- and post-test measurements were taken to give an indication of the effect of the tape on balance performance. Center of Pressure Excursion (COPE) and Time to Stabilization (TTS) when landing from a hop test and Y Balance test combined score (YBTCS) were used to assess a stabilizing balance activity and a dynamic balance. The pre- and post-intervention were collected, with differences explored using repeated measures ANOVA with time and condition (tape) factor analysis. Results: We found a significant improvement (p ≤ 0.05) with a moderate to large effect size in YBTCS between KT and no taping, indicating enhanced balance performance in the KT group. However, no significant difference (p ≥ 0.05) with small to moderate effect size was found in COPE or TTS between the two conditions during landing tests, suggesting similar balance capabilities in these specific measures. Conclusion: The use of KT shows no significant immediate effect on static balance in healthy individuals when applied to the quadriceps muscles; however, it demonstrates a positive immediate effect on dynamic balance.

Effects of 12 weeks of neuromuscular electrical stimulation of the quadriceps muscles on the function and physio-biochemical traits in functionally fit female nursing-home residents aged 75 + years: a pilot study.

PURPOSE: Muscular changes induced by neuromuscular electrical stimulation (NMES) are well recognized, but knowledge of how NMES influences the physio-biochemical traits of the oldest old is still limited. This study investigated the effect of NMES applied for 12 weeks to the quadriceps muscles of female nursing-home residents aged 75 + on their functional capability and inflammatory, bone metabolism, and cardiovascular traits. METHODS: Nineteen women regularly taking part in two body conditioning sessions per week were randomized into an electrical stimulation group (ES; n = 10; 30 min sessions, 3 times per week) or a control group (CON; n = 9). At baseline and study week 12, all women performed the 30 s chair stand test (30sCST), the 6-minute walk test (6MWT), and the instrumented timed up and go test (iTUG). Resting heart rates, blood pressure, and the blood concentrations of inflammatory and bone metabolism markers were also measured twice. RESULTS: NMES increased the strength of participants' quadriceps muscles and their performance on the 30sCST and 6MWT while lowering resting arterial blood pressure and inflammatory marker levels; osteoclast activity showed a tendency to decrease. Changes in the iTUG results were not observed. A multiple regression analysis found that the results of functional tests in the ES group were best correlated with pulse pressure (the 30sCST and iTUG tests) and diastolic blood pressure (the 6MWT test). CONCLUSION: Twelve weeks of NMES treatment improved participants' functional capacity and inflammatory, bone metabolism, and cardiovascular traits. The ES group participants' performance on functional tests was best predicted by hemodynamic parameters.

Comparison of the Agonist/Antagonist Tensional Balance of the Knee between Two Isokinetic Positions: A Pilot Study on a Sample of High-Level Competitive Soccer Players.

Isokinetic knee dynamometry evolves towards more precise techniques, such as the calculation of the functional ratio. This study evaluated the influence of an intermediate hip position called the unified reclined position (URP) compared to the classic sitting position, (CSP) on hamstring eccentric PT values (Hexc30) and conventional (Hcon60/Qcon60) and functional (Hexc30/Qcon60) ratios. Twenty Spanish high-level competitive soccer players (20.4 ± 4.44 years) were evaluated in CSP and in URP. The hip angle in URP (44°) was determined with a passive extensibility test (quadriceps and hamstrings), looking for an agonist/antagonist tension balance. The following were performed: three repetitions (60°/s) and five repetitions (240°/s) in concentric quadriceps and hamstrings mode; and three repetitions (30°/s) in concentric and eccentric for the hamstrings. At 30°/s, the CSP presents higher values of maximal eccentric hamstring strength than URP, (Dom + N-Dom leg (Nm): CSP = 148.3 ± 19.5 vs. URP 143.5 ± 23.2); p = 0.086 (n.s.). The conventional relationship did not show data justifying the preference for URP over CSP (p = 0.86 (n.s.)). However, although the functional index did not show significant values (p = 0.97 (n.s.), it did show a greater number of subjects with imbalances measured in URP (five in URP vs. two in CSP). An assessment angle of the hip closer to sports reality seems to favor the use of the URP as a complementary method to the CSP. These data stimulate new studies using URP together with the classic protocol.

The influence of knee varus and valgus on quadriceps muscle activity changes induced by stretching and kneeling.

This study aimed to determine the influence of knee varus (VARUS) and valgus (VALGUS) on the differences in individual quadriceps muscle (QM) activity during knee extension maximum voluntary isometric contractions (MVICs) and sit/stand transitions and on the changes in individual QM activity during sit/stand transitions after QM stretching and kneeling. Ten young healthy males each with VARUS and VALGUS were included. The electromyography signals of the vastus medialis (VM), vastus lateralis, and rectus femoris were recorded during sit/stand transitions before and after rest, stretching, and kneeling and during knee extension MVICs after rest. The individual muscle-to-total muscle activity ratio was assessed. The VARUS group exhibited a significantly higher VM muscle activity ratio in the sit-to-stand and stand-to-sit tasks than in knee extension MVICs (p = 0.004 and p = 0.044, respectively) and a tendency that the VM muscle activity ratio increased in the sit-to-stand task after stretching (p = 0.051), whereas the VALGUS group exhibited no significance. Individuals with VARUS required high VM muscle activity ratios during sit/stand transitions. Future studies should be conducted to determine whether habitual sit-to-stand exercises after QM stretching are effective in preventing knee medial osteoarthritis development in individuals with VARUS.

Dynamics of Quadriceps Muscles during Isometric Contractions: Velocity-Encoded Phase Contrast MRI Study.

OBJECTIVE: To quantify the spatial heterogeneity of displacement during voluntary isometric contraction within and between the different compartments of the quadriceps. METHODS: The thigh muscles of seven subjects were imaged on an MRI scanner while performing isometric knee extensions at 40% maximal voluntary contraction. A gated velocity-encoded phase contrast MRI sequence in axial orientations yielded tissue velocity-encoded dynamic images of the four different compartments of the thigh muscles (vastus lateralis (VL), vastus medialis (VM), vastus intermedius (VI), and rectus femoris (RF)) at three longitudinal locations of the proximal-distal length: 17.5% (proximal), 50% (middle), and 77.5% (distal). The displacement, which is the time integration of the measured velocity, was calculated along the three orthogonal axes using a tracking algorithm. RESULTS: The displacement of the muscle tissues was clearly nonuniform within each axial section as well as between the three axial locations. The ensemble average of the magnitude of the total displacement as a synthetic vector of the X, Y, and Z displacements was significantly larger in the VM at the middle location (p < 0.01), and in the VI at the distal location than in the other three muscles. The ensemble average of Z-axis displacement, which was almost aligned with the line of action, was significantly larger in VI than in the other three muscles in all three locations. Displacements of more than 20 mm were observed around the central aponeuroses, such as those between VI and the other surrounding muscles. CONCLUSIONS: These results imply that the quadriceps muscles act as one functional unit in normal force generation through the central aponeuroses despite complex behavior in each of the muscles, each of which possesses different physiological characteristics and architectures.

NEUROMUSCULAR ELECTRICAL STIMULATION OF MEDIUM AND LOW FREQUENCY ON THE QUADRICEPS FEMORIS.

OBJECTIVE: The purpose of this study was to investigate the effects of neuromuscular electrical stimulation (NMES) in different frequencies on the quadriceps femoris. A randomized, controlled, blind cross-sectional study. METHODS: Thirty subjects (12 men and 18 women), with an average age of 24.67 years, weight of 65.62 kg and height of 1.69 m were evaluated. Three random test conditions were applied: maximum voluntary isometric contraction (MVIC), maximum voluntary isometric contraction with medium frequency current (MVIC-MF) and maximum voluntary isometric contraction with low frequency current (MVIC-LF). Four MVICs were applied in each situation. The time between different isometric contraction types was 90 seconds while the time between the same conditions of contraction was 10 seconds. RESULTS: Two-way ANOVA test showed that MVIC-MF had higher values for peak torque than MVIC-LF (p=0.02). Significant statistical results were found when comparing MVIC-MF and MVIC (p=0.03), but not for MVIC and MVIC-LF (p=0.52). CONCLUSION: Maximum voluntary isometric contraction associated with medium-frequency electrical stimulation was more effective than other NMES conditions. Level of Evidence II, Therapeutic Studies - Investigation of treatment results.

OBJETIVO: A finalidade deste estudo foi investigar os efeitos da estimulação elétrica neuromuscular (EENM) em diferentes frequências sobre o músculo quadríceps femoral. Estudo randomizado, transversal, controlado e cego. MÉTODOS: Foram avaliados trinta indivíduos de ambos os sexos (12 homens e 18 mulheres) com média de idade de 24,67 anos, peso 65,62 kg e altura 1,69 m. Os indivíduos foram submetidos a três condições de testes randomizados: contração voluntária isométrica máxima (CVIM), contração voluntária isométrica máxima associada à corrente de média frequência (CVIMMF) e contração voluntária isométrica máxima associada à baixa frequência (CVIMBF), sendo realizadas quatro repetições de CVIM em cada situação. O tempo entre as diferentes condições de contrações isométricas foi de 90 segundos e o tempo entre as contrações isométricas das mesmas condições foi de 10 segundos. RESULTADOS: O teste ANOVA mostrou que a CVIMMF obteve valores de pico de torque maiores do que a CVIMBF (p = 0,02), com diferença significativa. Foram encontrados resultados com significância estatística ao comparar CVIMMF e CVIM (p = 0,03), mas não entre CVIM e CVIMBF (p = 0,52). CONCLUSÕES: A contração voluntária isométrica máxima associada a EENM de média frequência foi mais efetiva do que as outras situações de EENM. Nível de evidência II, Estudos Terapêuticos ­ Investigação dos resultados do tratamento.

Neuromuscular electrical stimulation of medium and low frequency on the quadriceps femoris / Estimulação elétrica neuromuscular de média e baixa frequência no músculo quadríceps femoral

ABSTRACT Objective: The purpose of this study was to investigate the effects of neuromuscular electrical stimulation (NMES) in different frequencies on the quadriceps femoris. A randomized, controlled, blind cross-sectional study. Methods: Thirty subjects (12 men and 18 women), with an average age of 24.67 years, weight of 65.62 kg and height of 1.69 m were evaluated. Three random test conditions were applied: maximum voluntary isometric contraction (MVIC), maximum voluntary isometric contraction with medium frequency current (MVIC-MF) and maximum voluntary isometric contraction with low frequency current (MVIC-LF). Four MVICs were applied in each situation. The time between different isometric contraction types was 90 seconds while the time between the same conditions of contraction was 10 seconds. Results: Two-way ANOVA test showed that MVIC-MF had higher values for peak torque than MVIC-LF (p=0.02). Significant statistical results were found when comparing MVIC-MF and MVIC (p=0.03), but not for MVIC and MVIC-LF (p=0.52). Conclusion: Maximum voluntary isometric contraction associated with medium-frequency electrical stimulation was more effective than other NMES conditions. Level of Evidence II, Therapeutic Studies - Investigation of treatment results.

RESUMO Objetivo: A finalidade deste estudo foi investigar os efeitos da estimulação elétrica neuromuscular (EENM) em diferentes frequências sobre o músculo quadríceps femoral. Estudo randomizado, transversal, controlado e cego. Métodos: Foram avaliados trinta indivíduos de ambos os sexos (12 homens e 18 mulheres) com média de idade de 24,67 anos, peso 65,62 kg e altura 1,69 m. Os indivíduos foram submetidos a três condições de testes randomizados: contração voluntária isométrica máxima (CVIM), contração voluntária isométrica máxima associada à corrente de média frequência (CVIMMF) e contração voluntária isométrica máxima associada à baixa frequência (CVIMBF), sendo realizadas quatro repetições de CVIM em cada situação. O tempo entre as diferentes condições de contrações isométricas foi de 90 segundos e o tempo entre as contrações isométricas das mesmas condições foi de 10 segundos. Resultados: O teste ANOVA mostrou que a CVIMMF obteve valores de pico de torque maiores do que a CVIMBF (p = 0,02), com diferença significativa. Foram encontrados resultados com significância estatística ao comparar CVIMMF e CVIM (p = 0,03), mas não entre CVIM e CVIMBF (p = 0,52). Conclusões: A contração voluntária isométrica máxima associada a EENM de média frequência foi mais efetiva do que as outras situações de EENM. Nível de evidência II, Estudos Terapêuticos - Investigação dos resultados do tratamento.

Ultrasonography and return to play of the different clinical grading of quadriceps contusions: a case series.

Prognostication of quadriceps contusion is based on the patient's active knee flexion after the injury. Unlike ultrasonography, clinical grading does not define the extent of soft tissue injury and may provide inaccurate time for return to play. The purposes of this report are to describe the ultrasound findings of the different clinical grading of quadriceps contusion and document the return to play of each case. Seven patients were evaluated in this series. Results showed discrepancies in the disability time between clinical grading and ultrasound findings. Clinical grading did not consistently estimate the return to play as described in previously published literature. Contusions with hyperechoic lesions had earlier return to play compared to patients with hypoechoic findings. Contusions with hypoechoic lesions might require aggressive monitoring and therapy to decrease disability time and avoid complications such as myositis ossificans.

Primary Motor Cortex Organization Is Altered in Persistent Patellofemoral Pain.

OBJECTIVE: Reorganization of the primary motor cortex (M1) may be a feature of persistent patellofemoral pain (PFP), but no studies have investigated M1 organization in this condition. Here we aimed to examine the organization of the M1 representation of the quadriceps muscles in people with PFP and healthy controls. DESIGN: Using a cross-sectional design, the M1 representation of the rectus femoris, vastus lateralis, and vastus medialis was mapped using transcranial magnetic stimulation in 11 individuals with PFP and 11 controls. Measures of pain severity were also made. RESULTS: Individuals with PFP had reduced map volumes (P < 0.001) and an anterior shift in the M1 representation (P = 0.03) across all three quadriceps muscles compared with controls. Greater overlap of the M1 representation (P = 0.02) and a reduction in the number of discrete cortical peaks (P = 0.009) across all three quadriceps muscles were also observed in individuals with PFP compared with controls. There was no relationship between altered M1 organization and pain in PFP. CONCLUSIONS: These findings provide evidence of altered M1 organization in individuals with PFP compared with healthy controls. Notably, no difference in M1 organization was observed for the medial and lateral heads of the quadriceps in PFP. These data have relevance for our understanding of the pathophysiology of PFP and for the design of future treatments that aim to target M1 in this condition.

Reliability of the Superimposed-Burst Technique in Patients With Patellofemoral Pain: A Technical Report.

CONTEXT: The superimposed-burst (SIB) technique is commonly used to quantify central activation failure after knee-joint injury, but its reliability has not been established in pathologic cohorts. OBJECTIVE: To assess within-session and between-sessions reliability of the SIB technique in patients with patellofemoral pain. DESIGN: Descriptive laboratory study. SETTING: University laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 10 patients with self-reported patellofemoral pain (1 man, 9 women; age = 24.1 ± 3.8 years, height = 167.8 ± 15.2 cm, mass = 71.6 ± 17.5 kg) and 10 healthy control participants (3 men, 7 women; age = 27.4 ± 5.0 years, height = 173.5 ± 9.9 cm, mass = 78.2 ± 16.5 kg) volunteered. INTERVENTION(S): Participants were assessed at 6 intervals spanning 21 days. Intraclass correlation coefficients (ICCs [3,3]) were used to assess reliability. MAIN OUTCOME MEASURE(S): Quadriceps central activation ratio, knee-extension maximal voluntary isometric contraction force, and SIB force. RESULTS: The quadriceps central activation ratio was highly reliable within session (ICC [3,3] = 0.97) and between sessions through day 21 (ICC [3,3] = 0.90-0.95). Acceptable reliability of knee extension (ICC [3,3] = 0.75-0.91) and SIB force (ICC [3,3] = 0.77-0.89) was observed through day 21. CONCLUSIONS: The SIB technique was reliable for clinical research up to 21 days in patients with patellofemoral pain.

Neural Excitability Alterations After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Neuromuscular dysfunction is common after anterior cruciate ligament reconstruction (ACL-R). However, little is known about quadriceps spinal-reflex and descending corticomotor excitability after ACL-R. Understanding the effects of ACL-R on spinal-reflex and corticomotor excitability will help elucidate the origins of neuromuscular dysfunction. OBJECTIVE: To determine whether spinal-reflex excitability and corticomotor excitability differed between the injured and uninjured limbs of patients with unilateral ACL-R and between these limbs and the matched limbs of healthy participants. DESIGN: Case-control study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 28 patients with unilateral ACL-R (9 men, 19 women; age = 21.28 ± 3.79 years, height = 170.95 ± 10.04 cm, mass = 73.18 ± 18.02 kg, time after surgery = 48.10 ± 36.17 months) and 29 participants serving as healthy controls (9 men, 20 women; age = 21.55 ± 2.70 years, height = 170.59 ± 8.93 cm, mass = 71.89 ± 12.70 kg) volunteered. MAIN OUTCOME MEASURE(S): Active motor thresholds (AMTs) were collected from the vastus medialis (VM) using transcranial magnetic stimulation. We evaluated VM spinal reflexes using the Hoffmann reflex normalized to maximal muscle responses (H : M ratio). Voluntary quadriceps activation was measured with the superimposed-burst technique and calculated using the central activation ratio (CAR). We also evaluated whether ACL-R patients with high or low voluntary activation had different outcomes. RESULTS: The AMT was higher in the injured than in the uninjured limb in the ACL-R group (t27 = 3.32, P = .003) and in the matched limb of the control group (t55 = 2.05, P = .04). The H : M ratio was bilaterally higher in the ACL-R than the control group (F1,55 = 5.17, P = .03). The quadriceps CAR was bilaterally lower in the ACL-R compared with the control group (F1,55 = 10.5, P = .002). The ACL-R group with low voluntary activation (CAR < 0.95) had higher AMT than the control group (P = .02), whereas the ACL-R group with high voluntary activation (CAR ≥ 0.95) demonstrated higher H : M ratios than the control group (P = .05). CONCLUSIONS: The higher VM AMT in the injured limbs of ACL-R patients suggested that corticomotor deficits were present after surgery. Higher bilateral H : M ratios in ACL-R patients may be a strategy to reflexively increase excitability to maintain voluntary activation.

Potentiation increases peak twitch torque by enhancing rates of torque development and relaxation.

The aim of this study was to measure the extent to which potentiation changes in response to an isometric maximal voluntary contraction. Eleven physically active subjects participated in two separate studies. Single stimulus of electrical stimulation of the femoral nerve was used to measure torque at rest in unpotentiated quadriceps muscles (study 1 and 2), and potentiated quadriceps muscles torque in a 10 min period after a 5 s isometric maximal voluntary contraction of the quadriceps muscles (study 1). Additionally, potentiated quadriceps muscles torque was measured every min after a further 10 maximal voluntary contractions repeated every min (study 2). Electrical stimulation repeated several times without previous maximal voluntary contraction showed similar peak twitch torque. Peak twitch torque 4 s after a 5 s maximal voluntary contraction increased by 45±13% (study 1) and by 56±10% (study 2), the rate of torque development by 53±13% and 82±29%, and the rate of relaxation by 50±17% and 59±22%, respectively, but potentiation was lost already two min after a 5 s maximal voluntary contraction. There was a tendency for peak twitch torque to increase for the first five repeated maximal voluntary contractions, suggesting increased potentiation with additional maximal voluntary contractions. Correlations for peak twitch torque vs the rate of torque development and for the rate of relaxation were r(2)= 0.94 and r(2)=0.97. The correlation between peak twitch torque, the rate of torque development and the rate of relaxation suggests that potentiation is due to instantaneous changes in skeletal muscle contractility and relaxation.

Two modes of weight training programs and patellar stabilization.

CONTEXT: Underconditioned patellar stabilizing muscles could be a predisposing factor for patellar instability. OBJECTIVE: To examine the effect of 2 modes of weight training on the size of the vastus medialis obliquus (VMO), the resting position and passive mobility of the patella, and the strength of the knee extensor muscles. DESIGN: Prospective intervention, repeated measures in 3 groups. SETTING: Orthopaedic and sports sciences research laboratory. PATIENTS OR OTHER PARTICIPANTS: 48 healthy adults free from back and lower extremity injuries. INTERVENTION(S): Participants were randomly assigned to muscle hypertrophy training, muscle strength training, or the control group. Those in the training groups pursued training 3 times per week for 8 weeks. MAIN OUTCOME MEASURE(S): Magnetic resonance imaging and ultrasound cross-sectional area of the VMO, patellar tilt angle on magnetic resonance imaging, instrumented passive patellar mobility, and isometric knee extension torque of the dominant leg. RESULTS: Participants in both training groups had comparable gains in VMO size, passive patellar stability, and knee extension force, all of which were greater than for the control group (P < .05). CONCLUSIONS: Both short-term muscle hypertrophy and strength training programs can reinforce the patellar stabilizers in previously untrained volunteers.