Effect of abdominal drawing-in maneuver during hip extension on the muscle onset time of gluteus maximus,hamstring, and lumbar erector spinae in subjects with hyperlordotic lumbar angle

Background

The abdominal drawing-in maneuver (ADIM) is used to prevent abnormal movements of the lumbar spine and pelvis during therapeutic exercises. This study compared the effects of ADIM on the muscle onset time of the hamstring, gluteus maximus, and erector spinae muscles during prone hip extension exercise in subjects with or without hyperlordotic lumbar angle. Forty healthy adults (18 male, 22 female) were recruited for this study.

Methods

The lumbar lordotic angles and pelvic tilt angles of the subjects were measured using the Avaliação postural analysis software. The subjects were divided into two groups: the lumbar hyperlordotic angle (LHLA) and lumbar normal lordotic angle (LNLA) groups. The muscle contraction onset time of the hamstring, gluteus maximus, and erector spinae were assessed using surface electromyography.

Results

During ADIM application, the muscle contraction onset time of the gluteus maximus was significantly increased in the LHLA group compared with the LNLA group.

Conclusions

ADIM application during prone hip extension was more effective for gluteus maximus onset time in the LHLA group. Therefore, ADIM during prone hip extension may be useful for gluteus maximus training in individuals with lumbar hyperlordosis.     

Use of antagonist muscle EMG in the assessment of neuromuscular health of the low back

Background

Non-specific low back pain (LBP) has been one of the most frequently occurring musculoskeletal problems. Impairment in the mechanical stability of the lumbar spine has been known to lower the safety margin of the spine musculature and can result in the occurrence of pain symptoms of the low back area. Previously, changes in spinal stability have been identified by investigating recruitment patterns of low back and abdominal muscles in laboratory experiments with controlled postures and physical activities that were hard to conduct in daily life. The main objective of this study was to explore the possibility of developing a reliable spine stability assessment method using surface electromyography (EMG) of the low back and abdominal muscles in common physical activities.

Methods

Twenty asymptomatic young participants conducted normal walking, plank, and isometric back extension activities prior to and immediately after maintaining a 10-min static upper body deep flexion on a flat bed. EMG data of the erector spinae, external oblique, and rectus abdominals were collected bilaterally, and their mean normalized amplitude values were compared between before and after the static deep flexion. Changes in the amplitude and co-contraction ratio values were evaluated to understand how muscle recruitment patterns have changed after the static deep flexion.

Results

Mean normalized amplitude of antagonist muscles (erector spinae muscles while conducting plank; external oblique and rectus abdominal muscles while conducting isometric back extension) decreased significantly (P < 0.05) after the 10-min static deep flexion. Normalized amplitude of agonist muscles did not vary significantly after deep flexion.

Conclusions

Results of this study suggest the possibility of using surface EMG in the evaluation of spinal stability and low back health status in simple exercise postures that can be done in non-laboratory settings. Specifically, amplitude of antagonist muscles was found to be more sensitive than agonist muscles in identifying changes in the spinal stability associated with the 10-min static deep flexion. Further research with various loading conditions and physical activities need to be performed to improve the reliability and utility of the findings of the current study.     

Association between individual quadriceps muscle volume/enthesis and patello femoral joint cartilage morphology

Introduction

The aim of this study was to determine the association between individual quadriceps muscle volumes and the quadriceps enthesis structures and cartilage morphology at the patellofemoral joint (PFJ).

Methods

We studied 12 cadavers (age 75 ± 5 years). For both legs, individual quadriceps muscles (vastus lateralis (VL), rectus femoris (RF), vastus intermedialis (VI) and vastus medialis (VM)) were dissected and their volumes measured. Cartilage areas at the PFJ were classified using the International Cartilage Repair Society (ICRS) score. Histological sections were evaluated at the quadriceps tendon enthesis (laterally, centrally and medially). Several variables were calculated on the binary images based on two-dimensional analysis. These were apparent bone area (BA) and apparent trabecular thickness (TH). A Spearman rank test was used to determine the strength of correlation between individual quadriceps muscles volume, the structure of the quadriceps tendon enthesis and the ICRS score.

Results

The thickness of calcified fibrocartilage tissue was significantly greater in the central part of the enthesis than both medially (P = 0.03) and laterally (P = 0.04). Uncalcified fibrocartilage was significantly thicker laterally (P = 0.04) and centrally (P = 0.02) than medially. Muscle volume was highest (P <0.05) for the VL, followed by the VI, VM and RF. There was no association between total and individual muscle volumes and ICRS or BA. However, there was a strong positive correlation (r = 0.81) between the VL/VM volume ratio and BA ratio (bone volume at the lateral part divided by bone volume at the medial part). There was a moderate positive correlation between VL/VM and ICRS (r = 0.65) and between ICRS and BA ratio (lateral/medial; r = 0.74).

Conclusions

Individual and total quadriceps volumes were not correlated with cartilage loss at the PFJ or fibrocartilage thickness. However, both VL/VM and BA ratio (lateral/medial) were positively correlated with ICRS scoring and therefore could be a tool for predicting degree of PFJ osteoarthritis severity.     

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.     

Balance of hip and trunk muscle activity is associated with increased anterior pelvic tilt during prone hip extension

Prone hip extension has been used as a self-perturbation task to test the stability of the lumbopelvic region. However, the relationship between recruitment patterns in the hip and trunk muscles and lumbopelvic kinematics remains unknown. The present study aimed to examine if the balance of hip and trunk muscle activities are related to pelvic motion and low back muscle activity during prone hip extension. Sixteen healthy participants performed prone hip extension from 30° of hip flexion to 10° of hip extension. Surface electromyography (of the gluteus maximus, semitendinosus, rectus femoris, tensor fasciae latae, multifidus, and erector spinae) and pelvic kinematic measurements were collected. Results showed that increased activity of the hip flexor (tensor fasciae latae) relative to that of hip extensors (gluteus maximus and semitendinosus) was significantly associated with increased anterior pelvic tilt during hip extension (r=0.52). Increased anterior pelvic tilt was also significantly related to the delayed onset timing of the contralateral and ipsilateral multifidus (r=0.57, r=0.53) and contralateral erector spinae (r=0.63). Additionally, the decrease of the gluteus maximus activity relative to the semitendinosus was significantly related to increased muscle activity of the ipsilateral erector spinae (r=-0.57). These results indicate that imbalance between the agonist and antagonist hip muscles and delayed trunk muscle onset would increase motion in the lumbopelvic region.     

Muscle-specific atrophy of the quadriceps femoris with aging.

We examined the size of the four muscles of the quadriceps femoris in young and old men and women to assess whether the vastus lateralis is an appropriate surrogate for the quadriceps femoris in human studies of aging skeletal muscle. Ten young (24 +/- 2 yr) and ten old (79 +/- 7 yr) sedentary individuals underwent magnetic resonance imaging of the quadriceps femoris after 60 min of supine rest. Volume (cm3) and average cross-sectional area (CSA, cm2) of the rectus femoris (RF), vastus lateralis (VL), vastus intermedius (VI), vastus medialis (VM), and the total quadriceps femoris were decreased (P < 0.05) in older compared with younger women and men. However, percentage of the total quadriceps femoris taken up by each muscle was similar (P > 0.05) between young and old (RF: 10 +/- 0.3 vs. 11 +/- 0.4; VL: 33 +/- 1 vs. 33 +/- 1; VI: 31 +/- 1 vs. 31 +/- 0.4; VM: 26 +/- 1 vs. 25 +/- 1%). These results suggest that each of the four muscles of the quadriceps femoris atrophy similarly in aging men and women. Our data support the use of vastus lateralis tissue to represent the quadriceps femoris muscle in aging research.     

Assessment of neuromuscular and haemodynamic activity in individuals with and without chronic low back pain

Background

Biering-Sørenson (1984) found that individuals with less lumbar extensor muscle endurance had an increased occurrence of first episode low back pain. As a result, back endurance tests have been recommended for inclusion in health assessment protocols. However, different studies have reported markedly different values for endurance times, leading some researchers to believe that the back is receiving support from the biceps femoris and gluteus maximus. Therefore, this study was designed to examine the haemodynamic and neuromuscular activity of the erector spinae, biceps femoris, and gluteus maximus musculature during the Biering-Sørenson Muscular Endurance Test (BSME).

Methods

Seventeen healthy individuals and 46 individuals with chronic low back pain performed the Biering-Sørenson Muscular Endurance Test while surface electromyography was used to quantify neuromuscular activity. Disposable silver-silver-chloride electrodes were placed in a bipolar arrangement over the right or left biceps femoris, gluteus maximus, and the lumbosacral paraspinal muscles at the level of L₃. Near Infrared Spectroscopy was used simultaneously to measure tissue oxygenation and blood volume changes of the erector spinae and biceps femoris.

Results

The healthy group displayed a significantly longer time to fatigue (Healthy: 168.5s, LBP: 111.1s; p ≤ 0.05). Significant differences were shown in the median frequency slope of the erector spinae between the two groups at 90–100% of the time to fatigue while no significant differences were noted in the haemodynamic data for the two groups.

Conclusion

Although the BSME has been recognized as a test for back endurance, individuals with chronic LBP appear to incorporate a strategy that may help support the back musculature by utilizing the biceps femoris and gluteus maximus to a greater degree than their healthy counterparts.

     

Experimental study of seita-fitting

The purpose of this study was to verify the difference between carrying a load on the sacrum (LOS) and on the lumbar vertebrae (LOL) in oxygen uptake, muscle activities, heart rate, cadence, and subjective response. Nine males (26.7 +/- 3.1 years old), each carrying a 7.5 kg carrier frame and a 40 kg load, walked on a treadmill at a speed of 50 m/min. EMGs were recorded from the trapezius, rectus abdominis, erector spinae, vastus lateralis, rectus femoris, vastus medialis, biceps femoris long head, tibial anterior, soleus, medial head of gastrocnemius, and the lateral head of gastrocnemius. For each subject the integrated EMG (IEMG) was normalized by dividing the IEMG in the LOL and LOS by the IEMG in a no-load condition (NL) for each investigated muscle. The following was significantly higher in LOL than in LOS: oxygen uptake; IEMG of the tibial anterior, soleus, and medial head of gastrocnemius; cadence; and rated perceived exertion. However, IEMG of the erector spinae was significantly lower in LOL than in LOS. These results suggest that seita-fitting in LOS causes a decrease of leg muscle activities, which causes oxygen uptake to decrease beyond the increase of the erector spinae activity.     

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.     

Changes in magnetic resonance images in human skeletal muscle after eccentric exercise

To investigate the time-course of changes in transverse relaxation time (T₂) and cross-sectional area (CSA) of the quadriceps muscle after a single session of eccentric exercise, magnetic resonance imaging was performed on six healthy male volunteers before and at 0, 7, 15, 20, 30 and 60 min and 12, 24, 36, 48, 72 and 168 h after exercise. Although there was almost no muscle soreness immediately after exercise, it started to increase 1 day after, peaking 1–2 days after the exercise (P<0.01). Immediately after exercise, T₂ increased significantly in the rectus femoris, vastus lateralis and intermedius muscles (P<0.05) and decreased quickly continuing until 60 min after exercise. At and after the 12th h, a significant increase was perceived again in the T₂ values of the vastus lateralis and intermedius muscles (P<0.01) [maximum 9.3 (SEM 2.8)% and 10.9 (SEM 2.2)%, respectively]. The maximal values were exhibited at 24–36 h after exercise. In contrast, the rectus femoris muscle showed no delayed-stage increase. Also, in CSA, an increase after 12 h was observed in addition to the one immediately after exercise in the vastus lateralis, intermedius and medialis and quadriceps muscles as a whole (P < 0.01), reaching the maximal values at 12–24 h after exercise. The plasma creative kinase activity remained unchanged up to 24 h after and then increased significantly 48 h after exercise (P < 0.05). Beginning 12 h after exercise, the subjects whose T₂ and CSA increased less than the others displayed a faster decrease in muscle soreness. These results suggested that T₂ and CSA displayed bimodal responses after eccentric exercise and the time-courses of changes in them were similar to those in muscle soreness.     

EMG activity of hip and trunk muscles during deep-water running

The present study used synchronized motion analysis to investigate the activity of hip and trunk muscles during deep-water running (DWR) relative to land walking (LW) and water walking (WW). Nine healthy men performed each exercise at self-determined slow, moderate, and fast paces, and surface electromyography was used to investigate activity of the adductor longus, gluteus maxima, gluteus medius, rectus abdominis, oblique externus abdominis, and erector spinae. The following kinematic parameters were calculated: the duration of one cycle, range of motion (ROM) of the hip joint, and absolute angles of the pelvis and trunk with respect to the vertical axis in the sagittal plane. The percentages of maximal voluntary contraction (%MVC) of each muscle were higher during DWR than during LW and WW. The %MVC of the erector spinae during WW increased concomitant with the pace increment. The hip joint ROMs were larger in DWR than in LW and WW. Forward inclinations of the trunk were apparent for DWR and fast-paced WW. The pelvis was inclined forward in DWR and WW. In conclusion, the higher-level activities during DWR are affected by greater hip joint motion and body inclinations with an unstable floating situation.     

A randomized clinical trial to assess the influence of a three months training program (Gym-based individualized vs. Calisthenics-based non-invidualized) in COPD-patients

Introduction

Pulmonary rehabilitation has been demonstrated to improve exercise capacity, dyspnoea, quality of life and to reduce the adverse effects of acute exacerbations. Current guidelines recommend exercise training in patients with mild to very severe disease. However, there is insufficient data comparing the efficacy of different training approaches and intensities.

Methods

Between January 2009 and December 2012, 105 COPD patients were screened to participate in the study. 61 patients were randomly assigned into an individualized training group or into a non-individualized training group. Both groups exercised once a week for 60 minutes over a time period of three months. At the beginning and after three months, the following measurements were performed: 6-minute walking test (6-MWT), health-related quality of life (St. Georges Respiratory Questionnaire; SGRQ and COPD-Assessment-Test; CAT), M. rectus femoris cross-sectional area, and inflammatory markers in peripheral blood.

Results

Only in the individualized training group we observed a significant change of the 6-MWT (increase of 32.47 m; p = 0.012) and the cross-sectional area of the M. rectus fermoris (increase of 0.57 cm²; p = 0.049), while no significant changes occurred in the non-individualized training group. Peroxisome-proliferator-activated receptor-γ coactivator 1α increased in the individualized training only after the three months training period (increase of 0.43 relative copies; p = 0.017), all other myokines and inflammatory markers were not influenced by either of the programs. The total drop-out-rate was 44.3%.

Conclusion

A low frequency outpatient training program may induce modest improvements in exercise capacity and muscle mass only if it is performed on an individualized basis.     

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     

Lumbar and abdominal muscle activity during walking in subjects with chronic low back pain: Support of the “guarding” hypothesis?

It has been hypothesized that changes in trunk muscle activity in chronic low back pain (CLBP) reflect an underlying “guarding” mechanism, which will manifest itself as increased superficial abdominal – and lumbar muscle activity. During a functional task like walking, it may be further provoked at higher walking velocities. The purpose of this cross sectional study was to investigate whether subjects with CLBP show increased co-activation of superficial abdominal – and lumbar muscles during walking on a treadmill, when compared to asymptomatic controls. Sixty-three subjects with CLBP and 33 asymptomatic controls walked on a treadmill at different velocities. Surface electromyography data of the erector spinae, rectus abdominis and obliquus abdominis externus muscles were obtained and averaged per stride. Results show that, compared to asymptomatic controls, subjects with CLBP have increased muscle activity of the erector spinae and rectus abdominis, but not of the obliquus abdominis externus. These differences in trunk muscle activity between groups do not increase with higher walking velocities. In conclusion, the observed increased trunk muscle activity in subjects with CLBP during walking supports the guarding hypothesis.     

PLAD (personal lift assistive device) stiffness affects the lumbar flexion/extension moment and the posterior chain EMG during symmetrical lifting tasks

The PLAD (personal lift assistive device) was designed to reduce the lumbar moment during lifting and bending tasks via elastic elements. This investigation examined the effects of modulating the elastic stiffness. Thirteen men completed 90 lifts (15 kg) using 6 different PLAD stiffnesses in stoop, squat and freestyle lifting postures. The activity of 8 muscles were recorded (latissimus dorsi, thoracic and lumbar erector spinae, rectus abdominis, external oblique, gluteus maximus, biceps femoris and rectus femoris), 3D electromagnetic sensors tracked the motion of each segment and strain gauges measured the elastic tension. EMG data were rectified, filtered, normalized and integrated as a percentage of the lifting task. The highest PLAD tension elicited the greatest reduction in erector spinae activity (mean of thoracic and lumbar) in comparison to the no-PLAD condition for the stoop (37%), squat (38%), and freestyle (37%) lifts, while prompting comparable reductions in gluteus maximums and biceps femoris activity. The highest PLAD stiffness also elicited the greatest reduction in the integrated L4/L5 flexion moment for the stoop (19.0%), squat (18.4%) and freestyle (17.4%) lifts without changing peak lumbar flexion. Each increase in PLAD stiffness further reduced the muscle activity of the posterior chain and the dynamic lumbar moment.     

Analysis of muscle activation during different leg press exercises at submaximum effort levels

Many studies have analyzed muscle activity during different strength exercises. Although the leg press (LP) is one of the most common exercises performed, there is little evidence of lower limb muscle activity patterns during this exercise and its variations. Thus, this study aimed to verify how mechanical changes and loads affect lower limb muscle activity during the performance of different LP exercises. Fourteen women performed 3 LP exercises: 45 degrees LP (LP45), LP high (LPH), and LP low (LPL) at 40% and 80% of the 1 repetition maximum. The electromyographic activity of the rectus femoris, vastus lateralis, biceps femoris, gastrocnemius, and gluteus maximus was recorded. Results suggested that mechanical changes affect lower limb muscle activity and that it is related to the load used. At moderate effort levels, the rectus femoris and gastrocnemius were more active during the LP45 and LPL than during the LPH. At a high effort level, the rectus femoris and vastus lateralis (quadriceps) were more active during the LPL than the LPH. Again, the rectus femoris and gastrocnemius were more active during the LP45 and LPL than the LPH. On the other hand, gluteus maximus activity was greater during the LPH than the LPL. This study found that coordination patterns of muscle activity are different when performing LP variations at high or moderate effort levels because of mechanical changes and different loads lifted during the different LP exercises. These results suggest that if the goal is to induce greater rectus femoris and vastus lateralis (quadriceps) activation, the LPL should be performed. On the other hand, if the goal is to induce gluteus maximus activity, the LPH should be performed.     

Rectus femoris and vastus intermedius fiber excursions predicted by three-dimensional muscle models

Computer models of the musculoskeletal system frequently represent the force-length behavior of muscle with a lumped-parameter model. Lumped-parameter models use simple geometric shapes to characterize the arrangement of muscle fibers and tendon; this may inaccurately represent changes in fiber length and the resulting force-length behavior, especially for muscles with complex architecture. The purpose of this study was to determine the extent to which the complex features of the rectus femoris and vastus intermedius architectures affect the fiber changes in length ("fiber excursions"). We created three-dimensional finite-element models of the rectus femoris and vastus intermedius muscles based on magnetic resonance (MR) images, and compared the fiber excursions predicted by the finite-element models with fiber excursions predicted by lumped-parameter models of these muscles. The finite-element models predicted rectus femoris fiber excursions (over a 100 degrees range of knee flexion) that varied from 55% to 70% of the excursion of the muscle-tendon unit and vastus intermedius fiber excursions that varied from 55% to 98% of the excursion muscle-tendon unit. In contrast, the lumped-parameter model of the rectus femoris predicted fiber excursions that were 86% of the excursion of the muscle-tendon unit and vastus intermedius fiber excursions that were 97% of the excursion of the muscle-tendon unit. These results suggest that fiber excursions of many fibers are overestimated in lumped-parameter models of these muscles. These new representations of muscle architecture can improve the accuracy of computer simulations of movement and provide insight into muscle design.     

The influence of increasing steady-state walking speed on muscle activity in below-knee amputees

The goal of this study was to identify changes in muscle activity in below-knee amputees in response to increasing steady-state walking speeds. Bilateral electromyographic (EMG) data were collected from 14 amputee and 10 non-amputee subjects during four overground walking speeds from eight intact leg and five residual leg muscles. Using integrated EMG measures, we tested three hypotheses for each muscle: (1) there would be no difference in muscle activity between the residual and intact legs, (2) there would be no difference in muscle activity between the intact leg and non-amputee legs, and (3) muscle activity in the residual and intact legs would increase with speed. Most amputee EMG patterns were similar between legs and increased in magnitude with speed. Differences occurred in the residual leg biceps femoris long head, vastus lateralis and rectus femoris, which increased in magnitude during braking compared to the intact leg. These adaptations were consistent with the need for additional body support and forward propulsion in the absence of the plantar flexors. With the exception of the intact leg gluteus medius, all intact leg muscles exhibited similar EMG patterns compared to the control leg. Finally, the residual, intact and control leg EMG all had a significant speed effect that increased with speed with the exception of the gluteus medius.     

Evaluation of Functional Limitations in Female Soccer Players and Their Relationship with Sports Level – A Cross Sectional Study

The main objective(s) of the study

The aim of this study was to analyze: a) abnormalities in the length of lower limb muscles, b) the correctness of movement patterns, and c) the impact of functional limitations of muscles on the correctness of fundamental movement patterns in a group of female soccer players, in relation to their skill level.

Materials and Methods

21 female soccer players from Polish Ekstraklasa and 22 players from the 1^st Division were tested for lower limb muscle length restrictions and level of fundamental movement skills (with the Fundamental Movement Screen™ test concept by Gray Cook). Chi-square test was used for categorical unrelated variables. Differences between groups in absolute point values were analyzed using the non-parametric Mann-Whitney U test. Statistical significance was set at p<0.05.

Results

Statistically significant higher number of measurements indicating an abnormal length of rectus femoris was observed in the 1st Division group (p = 0.0433). In the group of Ekstraklasa the authors obtained a significantly higher number of abnormal hamstring test results (p = 0.0006). Ekstraklasa players scored higher in the rotational stability test of the trunk (p = 0.0008), whereas the 1st Division players scored higher in the following tests: deep squat (p = 0.0220), in-line lunge (p = 0.0042) and active straight leg raise (p = 0.0125). The results suggest that there are different functional reasons affecting point values obtained in the FMS™ tests in both analyzed groups.

Conclusions

The differences in the flexibility of rectus femoris and hamstring muscle observed between female soccer players with different levels of training, may result from a long-term impact of soccer training on the muscle-tendon system and articular structures. Different causes of abnormalities in fundamental movement patterns in both analyzed groups suggest the need for tailoring prevention programs to the level of sport skills represented by the players.     

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.