Spyros Athanasopoulos

Intrinsic risk factors of non-contact quadriceps and hamstring strains in soccer: a prospective study of 100 professional players

Objectives To identify the intrinsic risk factors of non-contact strains in the hamstrings and quadriceps muscles of professional soccer players via a cohort prospective design. Methods A total of 100 professional soccer players (aged 19.4–27.8 years) from four professional teams underwent a composite musculoskeletal assessment at preseason. Intrinsic risk factors included dichotomies of asymmetries in muscle strength, flexibility, proprioception, anthropometry and knee joint stability, and of previous injuries. Muscle strains were prospectively monitored during the subsequent season using questionnaires. The data were analysed via binary logistic regression. Results Thirty-eight percent of the players sustained one or more lower-extremity muscle strains. Sixteen (42.1 %) and seven (18.4 %) of them were clinically diagnosed as having non-contact muscle strains at their hamstrings and quadriceps, respectively. Players with eccentric hamstring strength asymmetries (OR=3.88; 95% CI 1.13 to 13.23), functional leg length asymmetries (OR=3.80; 95% CI 1.08 to 13.33) and no previous hamstrings injuries (OR=0.15; 95% CI 0.029 to 0.79) were at greater risk of sustaining a hamstring muscle strain. Players with eccentric strength (OR=5.01; 95% CI 0.92 to 27.14) and flexibility asymmetries (OR=4.98; 95% CI 0.78 to 31.80) in their quadriceps as well as heavier (OR=10.70; 95% CI 0.73 to 156.37) and shorter players (OR=0.08; 95% CI 0.00 to 1.35) were at greater risk of sustaining a strain in this muscle group. Conclusions Professional soccer players with functional asymmetries possess a higher risk of sustaining hamstring strains. Previous injury seems not to constitute a risk factor. The systematic isokinetic evaluation of the lower extremities during the preseason period can provide therapists and trainers with valuable data regarding the predictive elements of non-contact hamstring strains in professional soccer players.

Lateralization of brain activity during lower limb joints movement. An fMRI study.

Studies of unilateral finger movement in right-handed subjects have shown asymmetrical patterns of activation in primary motor cortex and subcortical regions. In order to investigate the existence of an analogous pattern during lower limb joints movements, functional magnetic resonance imaging (fMRI) was used. Eighteen healthy, right leg dominant volunteers participated in a motor block design study, performing unilateral right and left repetitive knee, ankle and toes flexion/extension movements. Aiming to relate lower limb joints activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was also assessed. All movements were auditory paced at 72 beats/min (1.2 Hz). Brain activation during movement of the nondominant joints was more bilateral than during the same movement performed with the dominant joints. Finger movement had a stronger lateralized pattern of activation in comparison with lower limb joints, implying a different functional specialization. Differences were also evident between the joints of the lower limb. Ankle and toes movements elicited the same extend of MR signal change in the majority of the examined brain regions, whereas knee joint movement was associated with a different pattern. Finally, lateralization index in primary sensorimotor cortex and basal ganglia was significantly affected by the main effect of dominance, whereas the lateralization index in cerebellum was significantly affected by the joint main effect, demonstrating a lateralization index increase from proximal to distal joints.

Anterior Cruciate Ligament Deficiency Causes Brain Plasticity A Functional MRI Study

Background The mechanoreceptors located in anterior cruciate ligament (ACL) constitute an afferent source of information toward the central nervous system. It has been proposed that ACL deficiency causes a disturbance in neuromuscular control, affects central programs and consequently the motor response resulting in serious dysfunction of the injured limb. Purpose The objective of this study was to investigate whether chronic anterior cruciate ligament injury causes plastic changes in brain activation patterns. Study Design Case control study; Level of evidence, 3. Methods Seventeen right leg–dominant male participants with chronic anterior cruciate ligament deficiency and 18 matched healthy male participants with no special sport or habitual physical activity participated in this study. Patient selection criteria comprised a complete right unilateral anterior cruciate ligament rupture ≥6 months before testing. Brain activation was examined by using functional magnetic resonance imaging technique (1.5-T scanner). Results Results show that patients with anterior cruciate ligament deficiency had diminished activation in several sensorimotor cortical areas and increased activation in 3 areas compared with controls: presupplementary motor area, posterior secondary somatosensory area, and posterior inferior temporal gyrus. Conclusion The current study reveals that anterior cruciate ligament deficiency can cause reorganization of the central nervous system, suggesting that such an injury might be regarded as a neurophysiologic dysfunction, not a simple peripheral musculoskeletal injury. This evidence could explain clinical symptoms that accompany this type of injury and lead to severe dysfunction. Understanding the pattern of brain activation after a peripheral joint injury such as anterior cruciate ligament injury lead to new standards in rehabilitation and motor control learning with a wide application in a number of clinical and research areas (eg, surgical procedures, patient re-education, athletic training, etc).

Lower limb sensorimotor network: Issues of somatotopy and overlap

Functional magnetic resonance imaging (fMRI) was used (1) to describe the pattern of whole brain activity during motion of isolated joints of the lower limb, (2) to examine the somatotopic organization of lower limb joint representations in the primary sensorimotor cortex and the anterior lobe of the cerebellum and 3) to quantify the degree of overlap between these lower limb joint activations. Eighteen healthy, right leg dominant volunteers participated in a motor block-design study, performing repetitive knee, ankle and toes flexion/extension movements. In order to relate lower limb joints activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was also assessed. All movements were auditory paced at 72 beats/min (1.2 Hz). Isolated lower limb joints movement activated a distributed sensorimotor network, including primary and non-primary sensorimotor areas. Although a large overlap was evident in primary sensorimotor cortex (SM1) and cerebellum representations of the three lower limb joints, a somatotopic arrangement was recognizable with reference to center of mass coordinates of each individual joint in the above areas. Detection of active brain regions during movement of the lower limb joints is feasible with fMRI although a carefully optimized methodology protocol is required.

Quadriceps cross-sectional area changes in young healthy men with different magnitude of Q angle

Knee pain and dysfunction have been often associated with an ineffective pull of the patella by the vastus medialis (VM) relative to the vastus lateralis (VL), particularly in individuals with knee joint malalignment. Such changes in muscular behavior may be attributed to muscle inhibition and/or atrophy that precedes the onset of symptoms. The aim of this study was to investigate possible effects of knee joint malalignment, indicated by a high quadriceps (Q) angle (HQ angle >15 degrees ), on the anatomic cross-sectional area (aCSA) of the entire quadriceps and its individual parts, in a group of 17 young asymptomatic men compared with a group of 19 asymptomatic individuals with low Q angle (LQ angle <15 degrees ). The aCSA of the entire quadriceps (TQ), VM, VL, vastus intermedius (VI), rectus femoris (RF), and patellar tendon (PT) were measured during static and dynamic magnetic resonance imaging (MRI) with the quadriceps relaxed and under contraction, respectively. A statistically significant lower aCSA was obtained in the HQ angle group, compared with the LQ angle group, for the TQ, VL, and VI in both static (TQ = 9.9%, VL = 12.9%, and VI = 9.1%; P < 0.05) and dynamic imaging (TQ = 10.7%, P < 0.001; VL = 13.4%, P < 0.01; and VI = 9.8%, P < 0.05) and the aCSA of the VM in dynamic MRI (11.9%; P < 0.01). The muscle atrophy obtained in the HQ angle group may be the result of a protective mechanism that inhibits and progressively adapts muscle behavior to reduce abnormal loading and wear of joint structures.

Cross-cultural adaptation of the Greek version of the Knee Outcome Survey – Activities of Daily Living Scale (KOS-ADLS)

The purpose of this study was to cross-culturally adapt and validate the Greek version of Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS), a self-reported instrument used for patients with various knee pathological conditions including osteoarthritis. Ninety-four patients (57 males and 37 females) with a variety of pathological knee disorders and impairments being referred to physical therapy for evaluation and treatment were included in the study. For the crοss-cultural translation, a back-translation procedure was utilized by 3 bi-lingual translators. To assess test-retest reliability the patients were asked to complete the KOS-ADLS twice at initial visit; before and after physiotherapy treatment. To assess responsiveness, patients completed the KOS-ADLS at the end of all physiotherapy sessions and the score was compared with KOS-ADLS at initial (pre-treatment) visit. Finally, concurrent validity was measured by comparing the responses to the KOS-ADLS scores against the scores obtained from Visual Analogue Scale (VAS) and Global Rating Scale (GRS). Reliability was found satisfactory (ICC=0.97; SEM=3.03; SDD=23.05; Cronbachs alpha=0.98). Moreover, a gender subgroup analysis showed that women were more reliable than men. Minor floor/ceiling effects were detected. Concerning validity, all correlations were statistically significant, ranging from r=0.315 to r=0.741, however GRS presented higher correlations with KOS-ADLS in comparison with VAS. Finally, Greek KOS-ADLS was able to detect changes over time (standardized effect size=1.31 and standardized response mean=1.64). The Greek version of KOS-ADLS was found to be reliable, valid, responsive and comprehensible to use with patients with knee pathology.

EMG activation of trunk and upper limb muscles following experimentally-induced overpronation and oversupination of the feet in quiet standing

Kinematic studies have shown that experimentally-induced overpronation or oversupination of the subtalar joint may alter the position of the legs, hips and pelvis and consequently the trunk and upper limb. The purpose of the present study was to examine whether such foot deformity affects the activity of muscles that act on the trunk and upper limb. Twenty-eight healthy individuals (11 males and 17 females) 21.4±1.9 years of age without skeletal deformity, leg length discrepancy (LLD), overpronated or oversupinated feet or excessive lateral pelvic inclination volunteered for the study. Bilateral EMG recordings of the latissimus dorsi, pectoralis major and rectus abdominis were undertaken for 30-s with each subject in the relaxed standing position and at 5° and 10° bilateral or unilateral overpronation or oversupination of the foot on the dominant side using wooden wedge-shape blocks. The recorded EMG activity was normalised based on the EMG activity produced by the muscles under investigation during maximum isometric voluntary contraction. The findings of the present study revealed that neither bilateral nor unilateral overpronation/oversupination of the feet induced a significant alteration of the EMG activity of the latissimus dorsi, pectoralis major and rectus abdominis on either the dominant or non-dominant side. These findings suggest that in the absence of other major structural deformity bilateral or unilateral foot overpronation or oversupination does not affect the EMG activity of muscles that act on the trunk and upper limb in quiet standing.

Eversion and inversion muscle group peak torque in hyperpronated and normal individuals.

BACKGROUND Excessive subtalar pronation causes significant changes in the biomechanics of the lower leg, adversely influences proprioceptive feedback and neuromuscular reflex behavior and consequently, affects stability of the foot. However, the changes in muscle strength, caused by hyperpronation are unclear. OBJECTIVES The purpose of the present study was to compare the evertor and invertor peak torque between hyperpronated and normal individuals as well as between their dominant and non-dominant foot. METHOD 20 healthy male participants volunteered for this study. Leg dominance was assessed on the basis of a questionnaire and navicular drop measurements were used to classify participants into two groups: hyperpronated (> or =10 mm) and normals (5-9 mm). Isokinetic concentric eversion and inversion muscle group strength was tested at 30 degrees and 120 degrees/s using the Con-Trex MJ isokinetic dynamometer. RESULTS In all cases, inversion peak torque was greater than eversion peak torque and declined with increasing angular velocity. No significant differences were found for inversion and eversion concentric strength at both speeds tested, neither between normal and hyperpronated individuals neither between their dominant and non-dominant foot. CONCLUSIONS These results indicate the need re-evaluation of navicular drop values in order to identify normal and abnormal subtalar pronation. The assessment of eccentric contractions is also proposed when examining invertors and evertors isokinetic strength.

The effect of foot overpronation on Achilles tendon blood supply in healthy male subjects

The purpose of this study was to investigate Achilles tendon blood flow in individuals with overpronated feet during non‐weight‐ and weight‐bearing positions. Achilles tendon blood flow was measured by means of the pulsatility index (PI) and the resistance index (RI) in 15 male individuals with overpronated feet and 15 counterparts with normal feet, using power Doppler ultrasonography (PDI). Achilles tendon ultrasonographic (US) assessment was performed at its musculo‐tendinous junction (MTJ), mid‐tendon (MT), and osseotendinous junction (OTJ) at a non‐weight‐bearing relaxed position (RP) and during two‐leg stance (TLS) and one‐leg upright stance (OLS). PI and RI indices were significantly greater in individuals with overpronated feet compared to individuals with normal feet at the OTJ in OLS position (P < 0.01), and at MT in both TLS (P < 0.001) and OLS positions (P < 0.001). All individuals demonstrated also greater PI and RI indices at MT followed by the OTJ and MTJ in all positions (P < 0.001), and in OLS compared to TLS and the RP at the OTJ (P < 0.01) as well as at MT and MTJ (P < 0.001). The findings of the present study suggest that foot overpronation may affect Achilles tendon blood flow, particularly at mid‐tendon, thus enhancing the possibility for injury.

Scapular muscles’ activity in female volleyball players with scapular asymmetry in the resting position

BACKGROUND/AIM Resting scapular asymmetry with a more protracted and depressed position of the scapula in the dominant throwing side relative to the scapula of the contralateral side is commonly detected in overhead athletes with both healthy and disabled shoulders. It has been proposed that possible alterations in the EMG activity of periscapular muscles due to asymmetric position of the scapula may alter its kinematics leading to shoulder pathology. The aim of the current study was to identify possible alterations in the activation of periscapular muscles of healthy female volleyball players with scapular asymmetry in the resting position. METHODS Resting position of the scapula was determined in 37 healthy professional female volleyball players. Twenty-two players, with the scapula of the dominant side in a more protracted and depressed position compared to the non-dominant side, were classified as the asymmetry group. Fifteen players with almost symmetrical position of both scapulae comprised the control group. All participants performed an upper extremity closed chain exercise (knee push-ups) on a stable (floor) and an unstable surface (BOSU platform), while the EMG activity of serratus anterior (SA), upper trapezius (UT) and middle trapezius (MT) was recorded bilaterally. RESULTS No significant group (asymmetry vs. control) by side (dominant vs. non-dominant) by surface condition (floor vs. BOSU platform) interaction was detected with regard to the EMG activity of SA, UT and MT. Although not statistically significant the asymmetry group demonstrated a tendency for reduced EMG activity of the SA on the dominant compared to the contra-lateral side and compared to the dominant side of the control group. CONCLUSIONS The EMG activity of periscapular muscles (SA, UT and MT) was not affected during execution of a close chain exercise in healthy female volleyball players with the scapula of the dominant side in a more protracted and depressed resting position.