Association between walking ability and trunk and lower-limb muscle atrophy in institutionalized elderly women: a longitudinal pilot study

Background

The aim of this study was to investigate the association between walking ability and muscle atrophy in the trunk and lower limbs.

Methods

Subjects in this longitudinal study were 21 elderly women who resided in nursing homes. The thicknesses of the following trunk and lower-limb muscles were measured using B-mode ultrasound: rectus abdominis, external oblique, internal oblique, transversus abdominis, erector spinae, lumbar multifidus, psoas major, gluteus maximus, gluteus medius, gluteus minimus, rectus femoris, vastus lateralis, vastus intermedius, biceps femoris, gastrocnemius, soleus, and tibialis anterior. Maximum walking speed was used to represent walking ability. Maximum walking speed and muscle thickness were assessed before and after a 12-month period.

Results

Of the 17 measured muscles of the trunk and lower limbs, age-related muscle atrophy in elderly women was greatest in the erector spinae, rectus femoris, vastus lateralis, vastus intermedius, and tibialis anterior muscles. Correlation coefficient analyses showed that only the rate of thinning of the vastus lateralis was significantly associated with the rate of decline in maximum walking speed (r = 0.518, p < 0.05).

Conclusions

This longitudinal study suggests that reduced walking ability may be associated with muscle atrophy in the trunk and lower limbs, especially in the vastus lateralis muscle, among frail elderly women.     

Center of Pressure Displacement of Standing Posture during Rapid Movements Is Reorganised Due to Experimental Lower Extremity Muscle Pain

Background

Postural control during rapid movements may be impaired due to musculoskeletal pain. The purpose of this study was to investigate the effect of experimental knee-related muscle pain on the center of pressure (CoP) displacement in a reaction time task condition.

Methods

Nine healthy males performed two reaction time tasks (dominant side shoulder flexion and bilateral heel lift) before, during, and after experimental pain induced in the dominant side vastus medialis or the tibialis anterior muscles by hypertonic saline injections. The CoP displacement was extracted from the ipsilateral and contralateral side by two force plates and the net CoP displacement was calculated.

Results

Compared with non-painful sessions, tibialis anterior muscle pain during the peak and peak-to-peak displacement for the CoP during anticipatory postural adjustments (APAs) of the shoulder task reduced the peak-to-peak displacement of the net CoP in the medial-lateral direction (P<0.05). Tibialis anterior and vastus medialis muscle pain during shoulder flexion task reduced the anterior-posterior peak-to-peak displacement in the ipsilateral side (P<0.05).

Conclusions

The central nervous system in healthy individuals was sufficiently robust in maintaining the APA characteristics during pain, although the displacement of net and ipsilateral CoP in the medial-lateral and anterior-posterior directions during unilateral fast shoulder movement was altered.     

Pelvic Belt Effects on Health Outcomes and Functional Parameters of Patients with Sacroiliac Joint Pain

Introduction

The sacroiliac joint (SIJ) is a common source of low back pain. However, clinical and functional signs and symptoms correlating with SIJ pain are widely unknown. Pelvic belts are routinely applied to treat SIJ pain but without sound evidence of their pain-relieving effects. This case-control study compares clinical and functional data of SIJ patients and healthy control subjects and evaluates belt effects on SIJ pain.

Methods

17 SIJ patients and 17 healthy controls were included in this prospective study. The short-form 36 survey and the numerical rating scale were used to characterize health-related quality of life in patients in a six-week follow-up and the pain-reducing effects of pelvic belts. Electromyography data were obtained from the gluteus maximus, biceps femoris, rectus femoris and medial vastus. Alterations of muscle activity, variability and gait patterns were compared in patients and controls along with the belts’ effects in a dynamic setting when walking.

Results

Significant improvements were observed in the short-form 36 survey of the SIJ patients, especially in the physical health subscores. Minor declines were also observed in the numerical rating scale on pain. Belt-related changes of muscle activity and variability were similar in patients and controls with one exception: the rectus femoris activity decreased significantly in patients with belt application when walking. Further belt effects include improved cadence and gait velocity in patients and controls.

Conclusions

Pelvic belts improve health-related quality of life and are potentially attributed to decreased SIJ-related pain. Belt effects include decreased rectus femoris activity in patients and improved postural steadiness during locomotion. Pelvic belts may therefore be considered as a cost-effective and low-risk treatment of SIJ pain.

Trial Registration

ClinicalTrials.gov NCT02027038     

In vivo motion of the rectus femoris muscle after tendon transfer surgery

Rectus femoris transfer surgery is performed to convert the rectus femoris muscle from a knee extensor to a knee flexor. In this surgery, the distal tendon of the rectus femoris is detached from the patella and reattached to one of the knee flexor tendons. The outcomes of this procedure are variable, and it is not known if the surgery successfully converts the muscle to a knee flexor. We measured the motion of muscle tissue within the rectus femoris and vastus intermedius during knee extension in 10 unimpaired control subjects (10 limbs) and 6 subjects (10 limbs) after rectus femoris transfer using cine phase-contrast magnetic resonance imaging. Displacements of the vastus intermedius during knee extension were similar between control and tendon transfer subjects. In the control subjects, the rectus femoris muscle consistently moved in the direction of the knee extensors and displaced more than the vastus intermedius. The rectus femoris also moved in the direction of the knee extensors in the tendon transfer subjects; however, the transferred rectus femoris displaced less than the vastus intermedius. These results suggest that the rectus femoris is not converted to a knee flexor after its distal tendon is transferred to the posterior side of the knee, but its capacity for knee extension is diminished by the surgery.     

Test-retest reliability of EMG and peak torque during repetitive maximum concentric knee extensions.

The aim of this study was to investigate the reliability of peak torque and surface electromyography (EMG) variable's root mean square (RMS) and mean frequency (MNF) during an endurance test consisting of repetitive maximum concentric knee extensions. Muscle fatigue has been quantified in several ways, and in isokinetic testing it is based on a set of repetitive contractions. To assess test-retest reliability, two sets of 100 dynamic maximum concentric knee extensions were performed using an isokinetic dynamometer. The two series were separated by 7-8 days. The subjects relaxed during the passive flexion phase. Twenty (10 men and 10 women) clinically healthy subjects volunteered.Peak torque and EMG from rectus femoris, vastus medialis, vastus lateralis and biceps femoris were recorded. RMS and MNF were calculated from the EMG signal. The reliability was calculated with intraclass correlation coefficient ICC (1.1) and standard error of measurements (SEM). The reliability of peak torque was good (ICC=0.93) and SEM showed low values. ICC was good for absolute RMS of rectus femoris (ICC>/=0.80), vastus medialis (ICC>/=0.88) and vastus lateralis (ICC>/=0.82) and MNF of rectus femoris (ICC>/=0.82) and vastus medialis (ICC>/=0.83). Peak torque, and MNF and RMS of rectus femoris and vastus medialis are reliable variables obtained from an isokinetic endurance test of the knee extensors.     

Muscle Recruitment and Coordination following Constraint-Induced Movement Therapy with Electrical Stimulation on Children with Hemiplegic Cerebral Palsy: A Randomized Controlled Trial

Objective

To investigate changes of muscle recruitment and coordination following constraint-induced movement therapy, constraint-induced movement therapy plus electrical stimulation, and traditional occupational therapy in treating hand dysfunction.

Methods

In a randomized, single-blind, controlled trial, children with hemiplegic cerebral palsy were randomly assigned to receive constraint-induced movement therapy (n = 22), constraint-induced movement therapy plus electrical stimulation (n = 23), or traditional occupational therapy (n = 23). Three groups received a 2-week hospital-based intervention and a 6-month home-based exercise program following hospital-based intervention. Constraint-induced movement therapy involved intensive functional training of the involved hand during which the uninvolved hand was constrained. Electrical stimulation was applied on wrist extensors of the involved hand. Traditional occupational therapy involved functional unimanual and bimanual training. All children underwent clinical assessments and surface electromyography (EMG) at baseline, 2 weeks, 3 and 6 months after treatment. Surface myoelectric signals were integrated EMG, root mean square and cocontraction ratio. Clinical measures were grip strength and upper extremity functional test.

Results

Constraint-induced movement therapy plus electrical stimulation group showed both a greater rate of improvement in integrated EMG of the involved wrist extensors and cocontraction ratio compared to the other two groups at 3 and 6 months, as well as improving in root mean square of the involved wrist extensors than traditional occupational therapy group (p<0.05). Positive correlations were found between both upper extremity functional test scores and integrated EMG of the involved wrist as well as grip strength and integrated EMG of the involved wrist extensors (p<0.05).

Conclusions

Constraint-induced movement therapy plus electrical stimulation is likely to produce the best outcome in improving muscle recruitment and coordination in children with hemiplegic cerebral palsy compared to constraint-induced movement therapy alone or traditional occupational therapy.

Trial registration

chictr.org ChiCTR-TRC-13004041     

Length and moment arm of human leg muscles as a function of knee and hip-joint angles

Lengths of muscle tendon complexes of the quadriceps femoris muscle and some of its heads, biceps femoris and gastrocnemius muscles, were measured for six limbs of human cadavers as a function of knee and hip-joint angles. Length-angle curves were fitted using second degree polynomials. Using these polynomials the relationships between knee and hip-joint angles and moment arms were calculated. The effect of changing the hip angle on the biceps femoris muscle length is much larger than that of changing the knee angle. For the rectus femoris muscle the reverse was found. The moment arm of the biceps femoris muscle was found to remain constant throughout the whole range of knee flexion as was the case for the medial part of the vastus medialis muscle. Changes in the length of the lateral part of the vastus medialis muscle as well as the medial part of the vastus lateralis muscle are very similar to those of vastus intermedius muscle to which they are adjacent, while those changes in the length of the medial part of the vastus medialis muscle and the lateral part of the vastus lateralis muscle, which are similar to each other, differ substantially from those of the vastus intermedius muscle. Application of the results to jumping showed that bi-articular rectus femoris and biceps femoris muscles, which are antagonists, both contract eccentrically early in the push off phase and concentrically in last part of this phase.     

Potentiation of knee extensor contraction by antagonist conditioning contraction at several intensities

The purpose of this study was to examine the effect of graded conditioning contractions of the antagonist knee flexor muscles on the output characteristics of knee extensor muscles in healthy humans. Eight male university students performed maximum isometric contractions of knee extensors, preceded by isometric conditioning contractions of the antagonist knee flexors. The developed force and electromyographic (EMG) amplitudes of the knee extensors after the conditioning contraction were measured and compared with those of simple knee extension without conditioning. The forces of the conditioning flexor contraction were set at three levels: low (20% of maximum voluntary contraction: MVC), moderate (60% of MVC), and high (100% of MVC). The EMG amplitudes of the vastus medialis, vastus lateralis, and rectus femoris muscle were recorded and the root mean square amplitudes were calculated. The strongest enhancement of the extension force was obtained by moderate intensity conditioning contraction (108.95+/-1.87% of simple knee extension), although high intensity conditioning also induced a significant increase (105.41+/-2.69%). Low intensity conditioning did not cause a significant enhancement of the contraction force (103.17+/-2.99%). Similarly, the EMG amplitudes were significantly increased by moderate and/or high conditioning. These results suggest that antagonist conditioning contraction of moderate intensities is sufficient and may be optimal to potentiate knee extensor contraction.     

Simple Scoring System and Artificial Neural Network for Knee Osteoarthritis Risk Prediction: A Cross-Sectional Study

Background

Knee osteoarthritis (OA) is the most common joint disease of adults worldwide. Since the treatments for advanced radiographic knee OA are limited, clinicians face a significant challenge of identifying patients who are at high risk of OA in a timely and appropriate way. Therefore, we developed a simple self-assessment scoring system and an improved artificial neural network (ANN) model for knee OA.

Methods

The Fifth Korea National Health and Nutrition Examination Surveys (KNHANES V-1) data were used to develop a scoring system and ANN for radiographic knee OA. A logistic regression analysis was used to determine the predictors of the scoring system. The ANN was constructed using 1777 participants and validated internally on 888 participants in the KNHANES V-1. The predictors of the scoring system were selected as the inputs of the ANN. External validation was performed using 4731 participants in the Osteoarthritis Initiative (OAI). Area under the curve (AUC) of the receiver operating characteristic was calculated to compare the prediction models.

Results

The scoring system and ANN were built using the independent predictors including sex, age, body mass index, educational status, hypertension, moderate physical activity, and knee pain. In the internal validation, both scoring system and ANN predicted radiographic knee OA (AUC 0.73 versus 0.81, p<0.001) and symptomatic knee OA (AUC 0.88 versus 0.94, p<0.001) with good discriminative ability. In the external validation, both scoring system and ANN showed lower discriminative ability in predicting radiographic knee OA (AUC 0.62 versus 0.67, p<0.001) and symptomatic knee OA (AUC 0.70 versus 0.76, p<0.001).

Conclusions

The self-assessment scoring system may be useful for identifying the adults at high risk for knee OA. The performance of the scoring system is improved significantly by the ANN. We provided an ANN calculator to simply predict the knee OA risk.     

MMG and EMG responses of the superficial quadriceps femoris muscles.

Eighteen adults performed isometric muscle actions of the leg extensors at 25, 50, 75, and 100% maximal voluntary contraction (%MVC) at leg flexion angles of 25, 50, and 75 degrees. The results indicated that isometric torque production increased as leg flexion angle increased (75 degrees > 50 degrees > 25 degrees). For each muscle tested (rectus femoris, vastus lateralis, and vastus medialis), the EMG amplitude increased up to 100%MVC at each leg flexion angle (25, 50, and 75 degrees). The MMG amplitude for each muscle, however, increased up to 100%MVC at 25 and 50 degrees of leg flexion, but plateaued from 75 to 100%MVC at 75 degrees of leg flexion. We hypothesize that the varied patterns for the MMG amplitude-isometric torque relationships were due to leg flexion angle differences in: (1) muscle stiffness, (2) intramuscular fluid pressure, or (3) motor unit firing frequency.     

Knee angle-dependent oxygen consumption during isometric contractions of the knee extensors determined with near-infrared spectroscopy.

Fatigue resistance of knee extensor muscles is higher during voluntary isometric contractions at short compared with longer muscle lengths. In the present study we hypothesized that this would be due to lower energy consumption at short muscle lengths. Ten healthy male subjects performed isometric contractions with the knee extensor muscles at a 30, 60, and 90 degrees knee angle (full extension = 0 degrees ). At each angle, muscle oxygen consumption (m.VO2) of the rectus femoris, vastus lateralis, and vastus medialis muscle was obtained with near-infrared spectroscopy. m.VO2 was measured during maximal isometric contractions and during contractions at 10, 30, and 50% of maximal torque capacity. During all contractions, blood flow to the muscle was occluded with a pressure cuff (450 mmHg). m.VO2 significantly (P < 0.05) increased with torque and at all torque levels, and for each of the three muscles. m.VO2 was significantly lower at 30 degrees compared with 60 degrees and 90 degrees and m.VO2 was similar (P > 0.05) at 60 degrees and 90 degrees . Across all torque levels, average (+/- SD) m.VO2 at the 30 degrees angle for vastus medialis, rectus femoris, and vastus lateralis, respectively, was 70.0 +/- 10.4, 72.2 +/- 12.7, and 75.9 +/- 8.0% of the average m.VO2 obtained for each torque at 60 and 90 degrees . In conclusion, oxygen consumption of the knee extensors was significantly lower during isometric contractions at the 30 degrees than at the 60 degrees and 90 degrees knee angle, which probably contributes to the previously reported longer duration of sustained isometric contractions at relatively short muscle lengths.     

Identification of Novel Adipokines in the Joint. Differential Expression in Healthy and Osteoarthritis Tissues

Objectives

Emerging data suggest that several metabolic factors, released mainly by white adipose tissue (WAT) and joint tissues, and collectively named adipokines, might have a role in the pathophysiology of OA. Recently, novel adipokines such as SERPINE2, WISP2, GPNMB and ITIH5 have been identified in WAT. The main goal of this study was to analyse the expression of these novel adipokines in synovium, infrapatellar fat pad and chondrocytes and to compare the expression of these molecules in healthy and OA tissues.

Methods

Synovial tissues, infrapatellar fat pad and chondrocytes were obtained from 36 OA patients (age 52–85; mean BMI 28.9) who underwent total knee replacement surgery. Healthy synovial tissues and infrapatellar fat pad were obtained from 15 traumatic knee patients (age 23–53; mean BMI 23.5). mRNA and protein expression were determined by qRT-PCR and western blot analysis respectively.

Results

All the novel adipokines, matter of our study, are expressed in OA synovium, infrapatellar fat pad and chondrocytes. Moreover, we detected a differential expression of SERPINE2 and ITIH5 in OA synovial tissues as compared to healthy samples. Finally, we also observed an increased expression of WISP2 in OA infrapatellar fat pad in comparison to healthy controls.

Conclusions

In this study we demonstrated for the first time the expression of four novel adipokines in different joint tissues and how these molecules are differentially expressed in healthy and OA joint tissues.     

Characteristics of Patients at First Visit to a Polio Clinic in Sweden

Aim

Describe polio patients visiting a polio clinic in Sweden, a country where vaccination was introduced in 1957.

Design

A consecutive cohort study.

Patients

Prior polio patients.

Methods

All patients (n = 865) visiting the polio clinic at Sahlgrenska University Hospital, Gothenburg Sweden, between 1994 and 2012 were included in this study. Data at first visit regarding patient characteristics, polio classification, data of electromyography, origin, assistive devices and gait speed as well as muscle strength were collected for these patients. Twenty-three patients were excluded because no polio diagnosis could be established. A total of 842 patients with confirmed polio remained in the study.

Results

More than twenty percent of the patients were from countries outside the Nordic region and considerably younger than those from the Nordic region. The majority of the emigrants were from Asia and Africa followed by Europe (outside the Nordic region). Of all patients included ninety-seven percent (n = 817) had polio in the lower extremity and almost 53% (n = 444) had polio in the upper extremity while 28% (n = 238) had polio in the trunk, according to clinical classification of polio. Compared with a sample of the normal population, the polio patients walked 61–71% slower, and were 53–77% weaker in muscle strength of the knee and foot as well as grip strength.

Conclusion

The younger patients with polio emigrating from countries with different cultures may lead to a challenge for the multi professional teams working with post-polio rehabilitation and are of importance when planning for the care of polio patients the coming years.     

The addition of synchronous whole-body vibration to battling rope exercise increases skeletal muscle activity

Objectives:

To evaluate the effects of performing battling rope exercise with and without the addition of whole-body vibration (WBV) on muscle activity of the leg, trunk, and upper body.

Methods:

Twenty-eight recreationally active university students completed 20-s of battling rope undulation for 6 separate conditions: 1) alternating arm motion no WBV -Alt_NoWBV; 2) alternating arm motion 30 Hz low amplitude WBV -Alt_30 Hz-L; 3) alternating arm motion 50 Hz high amplitude -Alt_50 Hz-H; 4) double arm motion no WBV -Double_NoWBV; 5) double arm motion 30Hz low amplitude WBV -Double_30Hz-L; 6) double arm motion 50 `Hz high amplitude -Double_50 Hz-H. Electromyography (EMG) was measured for the gastrocnemius medialis (GM), vastus medialis oblique (VMO), vastus lateralis (VL), rectus abdominis (RA), multifidus (MF), biceps brachii (BB), and triceps brachii (TB) muscles.

Results:

The double arm motion during undulation resulted in greater (p<0.05) muscle activity in the VMO, VL, RA, and MF muscles while the GM was more active during the alternating arm motion. WBV at 50Hz increased EMG in all muscles measured vs NoWBV and the 30 Hz condition.

Conclusion:

These results are the first to demonstrate that the exercise stimulus of performing battling rope exercise can be augmented by completing the exercise while being exposed to WBV from a ground-based platform.     

Timing of neuromuscular activation of the quadriceps and hamstrings prior to landing in high school male athletes, female athletes, and female non-athletes.

There is a discrepancy between males and females in regards to lower extremity injury rates, particularly at the knee [Agel, J., Arendt, E.A., Bershadsky, B., 2005. Anterior cruciate ligament injury in National Collegiate Athletic Association basketball and soccer: a 13-year review. American Journal of Sports Medicine 33, (4) 524-530]. Gender differences in neuromuscular recruitment characteristics of the muscles that stabilize the knee are often implicated as a factor in this discrepancy. There is considerable research in the area of gender differences in regards to neuromuscular characteristics of the lower extremity in response to perturbation; however, most studies have been performed on the adult population only. Additionally, there is no consensus as to the gender differences that have been demonstrated. The purpose of this study was to compare muscular preactivation of selected lower extremity muscles (vastus medialis, rectus femoris, and medial/lateral hamstrings) in adolescent female basketball athletes, male basketball athletes, and female non-athletes in response to a drop landing. Subjects in the female non-athlete group recruited rectus femoris significantly slower than both the female athlete and male athlete groups (619.9=588.5>200.1ms prior to ground contact). The female non-athlete group also demonstrated a significantly slower vastus medialis compared to the female athlete group (127.1 vs 408.1ms), but not significantly slower than the male athlete group (127.1 vs 275.7ms). There were no differences between female athletes and male athletes for time to initial contraction of any muscle groups. No differences were found among the groups for medial or lateral hamstring activation. This study demonstrates that physical conditioning due to basketball participation appears to affect neuromuscular recruitment in adolescents and reveals a necessity to find alternate methods of training the hamstrings for improved neuromuscular capabilities to prevent injury.     

Age-related change in sit-to-stand power in Japanese women aged 50 years or older

Background

This study examined whether the age-related change in power, calculated from the score of a sit-to-stand (STS) test, corresponds to those in knee extension torque and leg lean tissue mass in Japanese women aged 50 years or older.

Findings

Time for a 10-times-repeated STS test and knee extension torque were determined in 556 Japanese women aged 50 to 94 years. STS power was calculated using an equation reported previously. In addition, leg lean tissue mass was estimated using muscle thicknesses determined at thigh and lower leg. STS power, knee extension torque, and lean tissue mass were negatively correlated to age. STS power and knee extension torque, expressed as the percentages of the mean value of the corresponding variable for the subjects aged 50 to 54 years were lower than that of lean tissue mass in the subjects aged 60 years or over, and were similar in those aged under 75 years. However, the relative value of STS power was lower than that of knee extension torque in the subjects aged over 75 years.

Conclusions

In Japanese women aged 50 to 74 years, STS power can be a convenient measure for assessing the age-related decline in knee extension torque, but not for leg lean tissue mass. At over 75 years old, the magnitude of the age-related decline in STS power does not parallel to that in the force generation capability of knee extensor muscles.     

Intra-Articular Corticosteroids in Addition to Exercise for Reducing Pain Sensitivity in Knee Osteoarthritis: Exploratory Outcome from a Randomized Controlled Trial

Objective

To assess the effects of one intra-articular corticosteroid injection two weeks prior to an exercise-based intervention program for reducing pain sensitivity in patients with knee osteoarthritis (OA).

Design

Randomized, masked, parallel, placebo-controlled trial involving 100 participants with clinical and radiographic knee OA that were randomized to one intra-articular injection on the knee with either 1 ml of 40 mg/ml methylprednisolone (corticosteroid) dissolved in 4 ml lidocaine (10 mg/ml) or 1 ml isotonic saline (placebo) mixed with 4 ml lidocaine (10 mg/ml). Two weeks after the injections all participants undertook a 12-week supervised exercise program. Main outcomes were changes from baseline in pressure-pain sensitivity (pressure-pain threshold [PPT] and temporal summation [TS]) assessed using cuff pressure algometry on the calf. These were exploratory outcomes from a randomized controlled trial.

Results

A total of 100 patients were randomized to receive either corticosteroid (n = 50) or placebo (n = 50); 45 and 44, respectively, completed the trial. Four participants had missing values for PPT and one for TS at baseline; thus modified intention-to-treat populations were analyzed. The mean group difference in changes from baseline at week 14 was 0.6 kPa (95% CI: -1.7 to 2.8; P = 0.626) for PPT and 384 mm×sec (95% CI: -2980 to 3750; P = 0.821) for TS.

Conclusions

These results suggest that adding intra-articular corticosteroid injection 2 weeks prior to an exercise program does not provide additional benefits compared to placebo in reducing pain sensitivity in patients with knee OA.

Trial Registration

EU clinical trials (EudraCT): 2012-002607-18     

Arthroscopically Assisted Combined Anterior and Posterior Cruciate Ligament Reconstruction with Autologous Hamstring Grafts–Isokinetic Assessment with Control Group

Objective

The aim of the study was to: 1) evaluate the differences in pre-post operative knee functioning, mechanical stability, isokinetic knee muscle strength in simultaneous arthroscopic patients after having undergone an anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) with hamstring tendons reconstruction, 2) compare the results of ACL/PCL patients with the control group.

Design

Controlled Laboratory Study.

Materials and Methods

Results of 11 ACL/PCL patients had been matched with 22 uninjured control participants (CP). Prior to surgery, and minimum 2 years after it, functional assessment (Lysholm and IKDC 2000), mechanical knee joint stability evaluation (Lachman and “drawer” test) and isokinetic tests (bilateral knee muscle examination) had been performed. Different rehabilitation exercises had been used: isometric, passive exercises, exercises increasing the range of motion and proprioception, strength exercises and specific functional exercises.

Results

After arthroscopy no significant differences had been found between the injured and uninjured leg in all isokinetic parameters in ACL/PCL patients. However, ACL/PCL patients had still shown significantly lower values of strength in relative isokinetic knee flexors (p = 0.0065) and extensors (p = 0.0171) compared to the CP. There were no differences between groups regarding absolute isokinetic strength and flexors/extensors ratio. There was statistically significant progress in IKDC 2000 (p = 0.0044) and Lysholm (p = 0.0044) scales prior to (44 and 60 points respectively) and after the reconstruction (61 for IKDC 2000 and 94 points for Lysholm).

Conclusions

Although harvesting tendons of semitendinosus and/or gracilis from the healthy extremity diminishes muscle strength of knee flexors in comparison to the CP, flexor strength had improved. Statistically significant improvement of the knee extensor function may indicate that the recreation of joint mechanical stability is required for restoring normal muscle strength. Without restoring normal muscle function and strength, surgical intervention alone may not be sufficient enough to ensure expected improvement of the articular function.     

Torque-related changes in mechanomyographic intensity patterns for the superficial quadriceps femoris muscles

The purpose of this study was to investigate changes in mechanomyographic (MMG) intensity patterns for the vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM) during submaximal to maximal concentric isokinetic, eccentric isokinetic and isometric muscle actions of the leg extensors. Eleven men (mean ± SD age = 20.1 ± 1.1 years) performed concentric, eccentric and isometric muscle actions of the dominant leg extensors on 3 separate days. Surface MMG signals were detected from the VL, RF and VM, processed with a wavelet analysis and examined with a trend plot. The results indicated that the trend plot was capable of tracking systematic changes in MMG amplitude and frequency with an increase in torque. However, these changes were statistically significant in only 26% of the cases. There were also no consistent differences between muscles or contraction types for the significance of the trend plots.