Influence of Position and Power Output on Upper Limb Kinetics in Cycling

2016 ◽  
Vol 32 (2) ◽  
pp. 140-149 ◽  
Author(s):  
Antony Costes ◽  
Nicolas A. Turpin ◽  
David Villeger ◽  
Pierre Moretto ◽  
Bruno Watier
Keyword(s):  
Upper Limb ◽  
Power Output ◽  
Inverse Dynamics ◽  
Random Order ◽  
Standing Position ◽  
Lower Limbs ◽  
Whole Body ◽  
Sit To Stand ◽  
Shoulder Joints ◽  
Limb Kinematics

Several suggestions on the upper limb involvement in cycling exist but, to date, no study has quantified upper limb kinetics in this task. The aim of this study was to determine how crank power and pedaling position (seated or standing) affect upper limb kinetics. Handlebar loadings and upper limb kinematics were collected from 17 participants performing seated or standing pedaling trials in a random order at 6 crank powers ranging from 20% (112 ± 19 W) to 120% (675 ± 113 W) of their spontaneous sit-to-stand transition power. An inverse dynamics approach was used to compute 3D moments, powers, and works at the wrist, elbow, and shoulder joints. Over 29 parameters investigated, increases in crank power were associated with increases in the magnitudes of 23 and 20 of the kinetic variables assessed in seated and standing positions, respectively. The standing position was associated with higher magnitudes of upper limb kinetics. These results suggest that both upper and lower limbs should be considered in future models to better understand whole body coordination in cycling.

EOS: A NEW IMAGING SYSTEM WITH LOW DOSE RADIATION IN STANDING POSITION FOR SPINE AND BONE & JOINT DISORDERS

2010 ◽  
Vol 13 (01) ◽  
pp. 1-12 ◽  
Author(s):  
Jean Dubousset ◽  
Georges Charpak ◽  
Wafa Skalli ◽  
Jacques Deguise ◽  
Gabriel Kalifa
Keyword(s):  
3D Reconstruction ◽  
Ct Scan ◽  
Low Dose ◽  
Imaging System ◽  
Standing Position ◽  
Lower Limbs ◽  
Whole Body ◽  
X Rays ◽  
Low Dose Radiation ◽  
Dose Radiation

Very precise combined work between multidisciplinary partners (radiation engineers in physics, engineers in biomechanics, medical radiologists and orthopedic pediatric surgeons) has led to the concept and development of a new low-dose radiation device named EOS. This device has three main advantages: (1) Thanks to the invention of Georges Charpak who designed gaseous detectors for X-rays, the reduction of dose necessary to obtain a good image of skeletal system was 8 to 10 times less for 2D imaging; compared to the dose necessary to obtain a 3D reconstruction from CT scan cuts, the reduction factor was 800 to 1000. (2) The accuracy of 3D reconstruction obtained is better than that of 3D reconstruction from CT scan cuts. (3) The patient in addition gets imaged in a standing functional position, thanks to the AP and lateral X-rays obtained from head to feet simultaneously. This is a big advantage compared to CT scans which are used only in lying position. From the simultaneous AP and lateral X-rays of the whole body obtained via the 3D bone external envelop technique, the biomechanics engineers obtain 3D reconstruction of every level of osteo-articular system, especially for spine, in standing position with an acceptable period of time for reconstruction. This (in spite of the evolution of standing MRI) allows more precise bone reconstruction in orthopedics, especially at the level of the entire skeleton, including the head, spine, pelvis, lower limbs, giving new consideration for physiology, physiopathology and therapeutics.

Comparison of Cylindrical Wrapping Geometries to Via Points for Modeling Muscle Paths in the Estimation of Sit-to-Stand Muscle Forces

2013 ◽  
Author(s):  
Valerie Norman-Gerum ◽  
John McPhee
Keyword(s):  
Muscle Force ◽  
Inverse Dynamics ◽  
Three Dimensional ◽  
Standing Position ◽  
Minimum Length ◽  
Muscle Forces ◽  
Joint Torques ◽  
Sit To Stand ◽  
Cylindrical Geometries ◽  
Anatomical Constraints

To better understand the complexities of rising from a seated to a standing position, a model of the human has been created. Sit-to-stand kinematics as well as ground reaction forces were measured experimentally and are used in an inverse dynamics analysis to estimate nine muscle forces during motion. Calculated muscle forces are sensitive to assumptions made when modeling muscle paths. Changes in the line of action of a muscle due to interaction with anatomical constraints are often accounted for by including fixed via points in a model. Here an alternate approach of representing anatomical constraints using three-dimensional cylindrical geometries is derived and presented. In this mathematical model the course of the muscle is determined as the minimum-length path where the muscle is allowed to wrap freely over the surface of the cylinder. Muscle forces are estimated for sit-to-stand by resolving net joint torques using an objective function giving preference to solutions minimizing both muscle stresses and abrupt changes in muscle forces. This is the first time muscle forces have been presented for sit-to-stand using a musculoskeletal model with included anatomical constraints represented using cylindrical wrapping geometries alone. A comparison of calculated muscle force patterns using fixed via points and wrapping points versus three-dimensional wrapping surfaces is made with reference to electromyographic phase data. For the sit-to-stand motion, the inclusion of anatomical constraints as three-dimensional cylindrical geometries results in calculation of muscle forces more true to the experimental data and more consistent with the belief that gradual motions are created by gradual changes in muscle force over time.

Sit-to-Stand Muscular Activity for Different Seat Backrest Inclination Levels and Execution Speeds

Motor Control ◽  
2020 ◽  
Vol 24 (4) ◽  
pp. 527-542
Author(s):  
Nadège Tebbache ◽  
Alain Hamaoui
Keyword(s):  
Muscular Activity ◽  
Surface Emg ◽  
Activity Level ◽  
Lower Limbs ◽  
Whole Body ◽  
Trunk Flexion ◽  
Sit To Stand ◽  
Maximal Speed ◽  
Execution Speed ◽  
Increased Activity

The sit-to-stand transfer can be separated into a postural phase (trunk flexion) and a focal phase (whole-body extension). The aim of this study was to analyze the as yet little known whole-body muscular activity characterizing each phase of this task and its variations with backrest inclination and execution speed. Fifteen muscles of the trunk and lower limbs of 10 participants were investigated using surface EMG. Results showed that backrest-induced modifications were mostly confined to the postural phase: reclining the backrest increased its duration and the activity level of the sternocleidomastoideus, the rectus and obliquus externus abdominis, and the semitendinosus. Speed-induced variations were also predominant during the postural phase, which was shortened with an increased activity of most muscles at maximal speed.

scholarly journals Effect of Seat Backrest Inclination on the Muscular Pattern and Biomechanical Parameters of the Sit-to-Stand

2021 ◽  
Vol 15 ◽  
Author(s):  
Nadège Tebbache ◽  
Alain Hamaoui
Keyword(s):  
Kinematic Chain ◽  
The Body ◽  
Activity Level ◽  
Lower Limbs ◽  
Upper Body ◽  
Whole Body ◽  
Activity Levels ◽  
Phase Duration ◽  
Sit To Stand ◽  
Biomechanical Parameters

Objectives: The sit-to-stand (STS) transfer mobilizes an extended part of the kinematic chain throughout a postural phase characterized by a flexion of the trunk and a focal phase consisting of a whole-body extension. The aim of this study was to analyze the variations of the global muscular pattern and the biomechanical parameters in both phases, in relation with seat backrest inclination.Methods: Fifteen participants were asked to stand up from a seat with 5 backrest inclination settings and at 2 execution speeds. The ground reaction forces and the activity levels of fifteen muscles of the trunk and lower limbs were investigated.Results: Backrest-induced modifications were mainly observed in the postural phase: inclining the backrest backward increased the phase duration and the activity level of the sternocleidomastoideus and the rectus abdominis, while it reduced the activity of the tibialis anterior. It also allowed for an increased maximal anteroposterior velocity of the body center of mass. Higher execution speed led to increased and earlier muscular activities of many trunk and lower limbs muscles, predominantly in the postural phase.Discussion: Taken together, these results suggest that a greater backrest inclination increases the demand in the postural phase due to the increase of the upper body gravity torque about the ischial tuberosities, and requires an adaptation of muscular activity levels and timing, but with the same overall pattern. The kinetic energy gained during the longer excursion of the trunk may also require less activation of the lower limbs muscles involved in the generation of propulsive forces of the body.

Acute Effect of Whole-Body Vibration at Optimal Frequency on Muscle Power Output of the Lower Limbs in Older Women

2013 ◽  
Vol 92 (9) ◽  
pp. 797-804 ◽  
Author(s):  
Arrigo Giombini ◽  
Andrea Macaluso ◽  
Luca Laudani ◽  
Annalisa Di Cesare ◽  
Alberto Piccinini ◽  
...  
Keyword(s):  
Older Women ◽  
Power Output ◽  
Muscle Power ◽  
Whole Body Vibration ◽  
Acute Effect ◽  
Lower Limbs ◽  
Whole Body ◽  
Optimal Frequency ◽  
Body Vibration ◽  
Muscle Power Output

Computed tomography angiography and microsurgical flaps for traumatic wounds: What is the added value?

2021 ◽  
pp. 1-9
Author(s):  
Lucas Sousa Macedo ◽  
Renato Polese Rusig ◽  
Gustavo Bersani Silva ◽  
Alvaro Baik Cho ◽  
Teng Hsiang Wei ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Upper Limb ◽  
Computed Tomography Angiography ◽  
Lower Limb ◽  
High Energy ◽  
Lower Limbs ◽  
Added Value ◽  
Vascular Lesions ◽  
Limb Injuries ◽  
Significant Difference

BACKGROUND: Microsurgical flaps are widely used to treat complex traumatic wounds of upper and lower limbs. Few studies have evaluated whether the vascular changes in preoperative computed tomography angiography (CTA) influence the selection of recipient vessel and type of anastomosis and the microsurgical flaps outcomes including complications. OBJECTIVE: The aim of this study was to evaluate if preoperative CTA reduces the occurrence of major complications (revision of the anastomosis, partial or total flap failure, and amputation) of the flaps in upper and lower limb trauma, and to describe and analyze the vascular lesions of the group with CTA and its relationship with complications. METHODS: A retrospective cohort study was undertaken with all 121 consecutive patients submitted to microsurgical flaps for traumatic lower and upper limb, from 2014 to 2020. Patients were divided into two groups: patients with preoperative CTA (CTA+) and patients not submitted to CTA (CTA–). The presence of postoperative complications was assessed and, within CTA+, we also analyzed the number of patent arteries on CTA and described the arterial lesions. RESULTS: Of the 121 flaps evaluated (84 in the lower limb and 37 in the upper limb), 64 patients underwent preoperative CTA. In the CTA+ group, 56% of patients with free flaps for lower limb had complete occlusion of one artery. CTA+ patients had a higher rate of complications (p = 0.031), which may represent a selection bias as the most complex limb injuries and may have CTA indicated more frequently. The highest rate of complications was observed in chronic cases (p = 0.034). There was no statistically significant difference in complications in patients with preoperative vascular injury or the number of patent arteries. CONCLUSIONS: CTA should not be performed routinely, however, CTA may help in surgical planning, especially in complex cases of high-energy and chronic cases, since it provides information on the best recipient artery and the adequate level to perform the microanastomosis, outside the lesion area.

scholarly journals Diagnostic Value of Whole-Body MRI Short Protocols in Bone Lesion Detection in Multiple Myeloma Patients

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1053
Author(s):  
Davide Ippolito ◽  
Teresa Giandola ◽  
Cesare Maino ◽  
Davide Gandola ◽  
Maria Ragusi ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow Involvement ◽  
Bone Lesion ◽  
Diagnostic Value ◽  
Lesion Detection ◽  
Lower Limbs ◽  
Whole Body ◽  
Bone Lesions ◽  
Whole Body Mri ◽  
Mri Protocol

The aim of the study is to evaluate the effectiveness of short whole-body magnetic resonance imaging (WBMRI) protocols for the overall assessment of bone marrow involvement in patients with multiple myeloma (MM), in comparison with standard whole-body MRI protocol. Patients with biopsy-proven MM, who underwent a WBMRI with full-body coverage (from vertex to feet) were retrospectively enrolled. WBMRI images were independently evaluated by two expert radiologists, in terms of infiltration patterns (normal, focal, diffuse, and combined), according to location (the whole skeleton was divided into six anatomic districts: skull, spine, sternum and ribs, upper limbs, pelvis and proximal two-thirds of the femur, remaining parts of lower limbs) and lytic lesions number (<5, 5–20, and >20). The majority of patients showed focal and combined infiltration patterns with bone lesions predominantly distributed in the spine and pelvis. As skull and lower limbs are less frequently involved by focal bone lesions, excluding them from the standard MRI protocol allows to obtain a shorter protocol, maintaining a good diagnostic value.

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