Recent findings suggest that not only the lack of physical activity, but also prolonged times of sedentary behaviour where major locomotor muscles are inactive, significantly increase the risk of chronic diseases. The purpose of this study was to provide details of quadriceps and hamstring muscle inactivity and activity during normal daily life of ordinary people. Eighty-four volunteers (44 females, 40 males, 44.1±17.3 years, 172.3±6.1 cm, 70.1±10.2 kg) were measured during normal daily life using shorts measuring muscle electromyographic (EMG) activity (recording time 11.3±2.0 hours). EMG was normalized to isometric MVC (EMG(MVC)) during knee flexion and extension, and inactivity threshold of each muscle group was defined as 90% of EMG activity during standing (2.5±1.7% of EMG(MVC)). During normal daily life the average EMG amplitude was 4.0±2.6% and average activity burst amplitude was 5.8±3.4% of EMG(MVC) (mean duration of 1.4±1.4 s) which is below the EMG level required for walking (5 km/h corresponding to EMG level of about 10% of EMG(MVC)). Using the proposed individual inactivity threshold, thigh muscles were inactive 67.5±11.9% of the total recording time and the longest inactivity periods lasted for 13.9±7.3 min (2.5-38.3 min). Women had more activity bursts and spent more time at intensities above 40% EMG(MVC) than men (p<0.05). In conclusion, during normal daily life the locomotor muscles are inactive about 7.5 hours, and only a small fraction of muscle's maximal voluntary activation capacity is used averaging only 4% of the maximal recruitment of the thigh muscles. Some daily non-exercise activities such as stair climbing produce much higher muscle activity levels than brisk walking, and replacing sitting by standing can considerably increase cumulative daily muscle activity.
Back extension exercises are often used in the rehabilitation of low back pain. However, at present it is not clear how the posterior muscles are recruited during different types of extension exercises. Therefore the present study will evaluate the myoelectric activity of thoracic, lumbar and hip extensor muscles during different extension exercises in healthy persons. Based on these physiological observations we will make recommendations regarding the use of extensions exercises in clinical practice.
INTRODUCTION: Mycotic aneurysms are rarely listed among the possible complications of osteomyelitis of the long bones. To the best of our knowledge this is the first case of chronic osteomyelitis associated with a pathological fracture of the femur and a mycotic aneurysm of the femoral artery. CASE PRESENTATION: We present the case of a 13-year-old Ugandan boy who was referred to our hospital with chronic osteomyelitis associated with a pathological fracture of the right femur and a mycotic aneurysm of the femoral artery. He underwent a successful above-knee amputation and is currently undergoing rehabilitation. CONCLUSIONS: Aneurysms associated with chronic osteomyelitis of the long bones are very rare. However, in Africa, where people often still believe in crude traditional remedies, they should be considered among the possible diagnoses especially where acute injuries of the limbs are massaged and manipulated.
AIM OF THE STUDY: The aim of this study was to describe an individual’s 3-dimensional buttocks response to sitting. Within that exploration, we specifically considered tissue (i.e., fat and muscle) deformations, including tissue displacements that have not been identified by research published to date. MATERIALS AND METHODS: The buttocks anatomy of an able-bodied female during sitting was collected in a FONAR Upright MRI. T1-weighted Fast Spin Echo scans were collected with the individual seated on a custom wheelchair cushion with a cutout beneath the pelvis (“unloaded”), and seated on a 3″ foam cushion (“loaded”). 2D slices of the MRI were analyzed, and bone and muscle were segmented to permit 3D rendering and analyses. RESULTS: MRIs indicated a marked decrease in muscle thickness under the ischial tuberosity during loaded sitting. This change in thickness resulted from a combination of muscle displacement and distortion. The gluteus and hamstrings overlapped beneath the pelvis in an unloaded condition, enveloping the ischial tuberosity. But the overlap was removed under load. The hamstrings moved anteriorly, while the gluteus moved posterior-laterally. Under load, neither muscle was directly beneath the apex of the ischial tuberosity. Furthermore, there was a change in muscle shape, particularly posterior to the peak of the ischial tuberosity. CONCLUSION: The complex deformation of buttocks tissue seen in this case study may help explain the inconsistent results reported in finite element models. 3D imaging of the seated buttocks provides a unique opportunity to study the actual buttocks response to sitting.
The quadriceps femoris is traditionally described as a muscle group composed of the rectus femoris and the three vasti. However, clinical experience and investigations of anatomical specimens are not consistent with the textbook description. We have found a second tensor-like muscle between the vastus lateralis (VL) and the vastus intermedius (VI), hereafter named the tensor VI (TVI). The aim of this study was to clarify whether this intervening muscle was a variation of the VL or the VI, or a separate head of the extensor apparatus. Twenty-six cadaveric lower limbs were investigated. The architecture of the quadriceps femoris was examined with special attention to innervation and vascularization patterns. All muscle components were traced from origin to insertion and their affiliations were determined. A TVI was found in all dissections. It was supplied by independent muscular and vascular branches of the femoral nerve and lateral circumflex femoral artery. Further distally, the TVI combined with an aponeurosis merging separately into the quadriceps tendon and inserting on the medial aspect of the patella. Four morphological types of TVI were distinguished: Independent-type (11/26), VI-type (6/26), VL-type (5/26), and Common-type (4/26). This study demonstrated that the quadriceps femoris is architecturally different from previous descriptions: there is an additional muscle belly between the VI and VL, which cannot be clearly assigned to the former or the latter. Distal exposure shows that this muscle belly becomes its own aponeurosis, which continues distally as part of the quadriceps tendon. Clin. Anat., 2015. © 2016 Wiley Periodicals, Inc.
Manipulating joint range of motion during squat training may have differential effects on adaptations to strength training with implications for sports and rehabilitation. Consequently, the purpose of this study was to compare the effects of squat training with a short vs. a long range of motion. Male students (n = 17) were randomly assigned to 12 weeks of progressive squat training (repetition matched, repetition maximum sets) performed as either a) deep squat (0-120° of knee flexion); n = 8 (DS) or (b) shallow squat (0-60 of knee flexion); n = 9 (SS). Strength (1 RM and isometric strength), jump performance, muscle architecture and cross-sectional area (CSA) of the thigh muscles, as well as CSA and collagen synthesis in the patellar tendon, were assessed before and after the intervention. The DS group increased 1 RM in both the SS and DS with ~20 ± 3 %, while the SS group achieved a 36 ± 4 % increase in the SS, and 9 ± 2 % in the DS (P < 0.05). However, the main finding was that DS training resulted in superior increases in front thigh muscle CSA (4-7 %) compared to SS training, whereas no differences were observed in patellar tendon CSA. In parallel with the larger increase in front thigh muscle CSA, a superior increase in isometric knee extension strength at 75° (6 ± 2 %) and 105° (8 ± 1 %) knee flexion, and squat-jump performance (15 ± 3 %) were observed in the DS group compared to the SS group. Training deep squats elicited favourable adaptations on knee extensor muscle size and function compared to training shallow squats.
Many studies suggest that impairment of motor control is the mechanical component of the pathogenesis of painful disorders in the lumbo-sacral region; however, this theory is still unproven and the results and recommendations for intervention remain questionable. The need for a force to compress both innominate bones against the sacrum is the basis for treatment of pregnancy-related pelvic girdle pain (PGP). Therefore, it is advised to use a pelvic belt and do exercises to enhance contraction of the muscles which provide this compression. However, our clinical experience is that contraction of those muscles appears to be excessive in PGP. Therefore, in patients with long-lasting pregnancy-related posterior PGP, there is a need to investigate the contraction pattern of an important muscle that provides a compressive force, i.e. the transverse abdominal muscle (TrA), during a load transfer test, such as active straight leg raising (ASLR).
The objective of this study was to investigate biomechanical loading to the low back as a result of wearing an exoskeletal intervention designed to assist in occupational work. Twelve subjects simulated the use of two powered hand tools with and without the use of a Steadicam vest with an articulation tool support arm in a laboratory environment. Dependent measures of peak and mean muscle forces in ten trunk muscles and peak and mean spinal loads were examined utilizing a dynamic electromyography-assisted spine model. The exoskeletal device increased both peak and mean muscle forces in the torso extensor muscles (p < 0.001). Peak and mean compressive spinal loads were also increased up to 52.5% and 56.8%, respectively, for the exoskeleton condition relative to the control condition (p < 0.001). The results of this study highlight the need to design exoskeletal interventions while anticipating how mechanical loads might be shifted or transferred with their use.
This randomized controlled trial examined the effects of multicomponent training on muscle power output, muscle mass, and muscle tissue attenuation; the risk of falls; and functional outcomes in frail nonagenarians. Twenty-four elderly (91.9 ± 4.1 years old) were randomized into intervention or control group. The intervention group performed a twice-weekly, 12-week multicomponent exercise program composed of muscle power training (8-10 repetitions, 40-60 % of the one-repetition maximum) combined with balance and gait retraining. Strength and power tests were performed on the upper and lower limbs. Gait velocity was assessed using the 5-m habitual gait and the time-up-and-go (TUG) tests with and without dual-task performance. Balance was assessed using the FICSIT-4 tests. The ability to rise from a chair test was assessed, and data on the incidence and risk of falls were assessed using questionnaires. Functional status was assessed before measurements with the Barthel Index. Midthigh lower extremity muscle mass and muscle fat infiltration were assessed using computed tomography. The intervention group showed significantly improved TUG with single and dual tasks, rise from a chair and balance performance (P < 0.01), and a reduced incidence of falls. In addition, the intervention group showed enhanced muscle power and strength (P < 0.01). Moreover, there were significant increases in the total and high-density muscle cross-sectional area in the intervention group. The control group significantly reduced strength and functional outcomes. Routine multicomponent exercise intervention should be prescribed to nonagenarians because overall physical outcomes are improved in this population.
As compared with injuries involving muscle only, those involving the central hamstring tendon have a worse prognosis. Limited information is available regarding the surgical treatment of central tendon injuries of the hamstrings.