Multi-Kinect skeleton fusion for physical rehabilitation monitoring

 Kinect has been increasingly applied in rehabilitation as a motion capture device. However, the inherent limitations significantly hinder its further development in this important area. Although a number of Kinect fusion approaches have been proposed, only a few of them was actually considered for rehabilitation. In this paper, we propose to fuse information from multiple Kinects to achieve this. Given the specific scenario of users suffering from limited range of movements, we propose to calibrate depth cameras in multiple Kinects with 3D positions of joints on a human body rather than in a checkerboard pattern, so that patients are able to calibrate Kinects without extra support. Kalman filter is applied for skeleton-wise Kinect fusion since skeleton data (3D positions of joints) and its derivatives are preferred by physiotherapists to evaluate the exercise performance of patients. Various preliminary experiments were conducted to illustrate the accuracy of proposed calibration and fusion approach by comparing with a commercial Vicon system®, confirming the practical use of the system in rehabilitation exercise monitoring.

The CDP-Ethanolamine Pathway Regulates Skeletal Muscle Diacylglycerol Content and Mitochondrial Biogenesis without Altering Insulin Sensitivity.

Accumulation of diacylglycerol (DG) in muscle is thought to cause insulin resistance. DG is a precursor for phospholipids, thus phospholipid synthesis could be involved in regulating muscle DG. Little is known about the interaction between phospholipid and DG in muscle; therefore, we examined whether disrupting muscle phospholipid synthesis, specifically phosphatidylethanolamine (PtdEtn), would influence muscle DG content and insulin sensitivity. Muscle PtdEtn synthesis was disrupted by deleting CTP:phosphoethanolamine cytidylyltransferase (ECT), the rate-limiting enzyme in the CDP-ethanolamine pathway, a major route for PtdEtn production. While PtdEtn was reduced in muscle-specific ECT knockout mice, intramyocellular and membrane-associated DG was markedly increased. Importantly, however, this was not associated with insulin resistance. Unexpectedly, mitochondrial biogenesis and muscle oxidative capacity were increased in muscle-specific ECT knockout mice and were accompanied by enhanced exercise performance. These findings highlight the importance of the CDP-ethanolamine pathway in regulating muscle DG content and challenge the DG-induced insulin resistance hypothesis.

Changes in mitochondrial function and mitochondria associated protein expression in response to 2-weeks of high intensity interval training

PURPOSE: High-intensity short-duration interval training (HIT) stimulates functional and metabolic adaptation in skeletal muscle, but the influence of HIT on mitochondrial function remains poorly studied in humans. Mitochondrial metabolism as well as mitochondrial-associated protein expression were tested in untrained participants performing HIT over a 2-week period. METHODS: Eight males performed a single-leg cycling protocol (12 × 1 min intervals at 120% peak power output, 90 s recovery, 4 days/week). Muscle biopsies (vastus lateralis) were taken pre- and post-HIT. Mitochondrial respiration in permeabilized fibers, citrate synthase (CS) activity and protein expression of peroxisome proliferator-activated receptor gamma coactivator (PGC-1α) and respiratory complex components were measured. RESULTS: HIT training improved peak power and time to fatigue. Increases in absolute oxidative phosphorylation (OXPHOS) capacities and CS activity were observed, but not in the ratio of CCO to the electron transport system (CCO/ETS), the respiratory control ratios (RCR-1 and RCR-2) or mitochondrial-associated protein expression. Specific increases in OXPHOS flux were not apparent after normalization to CS, indicating that gross changes mainly resulted from increased mitochondrial mass. CONCLUSION: Over only 2 weeks HIT significantly increased mitochondrial function in skeletal muscle independently of detectable changes in mitochondrial-associated and mitogenic protein expression.

The role and regulation of erythropoietin (EPO) and its receptor in skeletal muscle: how much do we really know?

Erythropoietin (EPO) primarily activates erythroid cell proliferation and growth and is active in several types of non-hematopoietic cells via its interaction with the EPO-receptor (EPO-R). This review focuses on the role of EPO in skeletal muscle. The EPO-R is expressed in skeletal muscle cells and EPO may promote myoblast differentiation and survival via the activation of the same signaling cascades as in hematopoietic cells, such as STAT5, MAPK and Akt. Inconsistent results exist with respect to the detection of the EPO-R mRNA and protein in muscle cells, tissue and across species and the use of non-specific EPO-R antibodies contributes to this problem. Additionally, the inability to reproducibly detect an activation of the known EPO-induced signaling pathways in skeletal muscle questions the functionality of the EPO-R in muscle in vivo. These equivocal findings make it difficult to distinguish between a direct effect of EPO on skeletal muscle, via the activation of its receptor, and an indirect effect resulting from a better oxygen supply to the muscle. Consequently, the precise role of EPO in skeletal muscle and its regulatory mechanism/s remain to be elucidated. Further studies are required to comprehensively establish the importance of EPO and its function in skeletal muscle health.

Flying, fasting, and feeding in birds during migration: a nutritional and physiological ecology perspective

Unlike exercising mammals, migratory birds fuel very high intensity exercise (e.g., flight) with fatty acids delivered from the adipose tissue to the working muscles by the circulatory system. Given the primary importance of fatty acids for fueling intense exercise, we discuss the likely limiting steps in lipid transport and oxidation for exercising birds and the ecological factors that affect the quality and quantity of fat stored in wild birds. Most stored lipids in migratory birds are comprised of three fatty acids (16:0, 18:1 and 18:2) even though migratory birds have diverse food habits. Diet selection and selective metabolism of lipids play important roles in determining the fatty acid composition of birds which, in turn, affects energetic performance during intense exercise. As such, migratory birds offer an intriguing model for studying the implications of lipid metabolism and obesity on exercise performance. We conclude with a discussion of the energetic costs of migratory flight and stopover in birds, and its implications for bird migration strategies.

Fluid intake, hydration, work physiology of wildfire fighters working in the heat over consecutive days

PURPOSE: (i) To evaluate firefighters' pre- and post-shift hydration status across two shifts of wildfire suppression work in hot weather conditions. (ii) To document firefighters' fluid intake during and between two shifts of wildfire suppression work. (iii) To compare firefighters' heart rate, activity, rating of perceived exertion (RPE), and core temperature across the two consecutive shifts of wildfire suppression work. METHOD: Across two consecutive days, 12 salaried firefighters' hydration status was measured immediately pre- and post-shift. Hydration status was also measured 2h post-shift. RPE was also measured immediately post-shift on each day. Work activity, heart rate, and core temperature were logged continuously during each shift. Ten firefighters also manually recorded their food and fluid intake before, during, and after both fireground shifts. RESULTS: Firefighters were not euhydrated at all measurement points on Day one (292±1 mOsm l(-1)) and euhydrated across these same time points on Day two (289±0.5 mOsm l(-1)). Fluid consumption following firefighters' shift on Day one (1792±1134ml) trended (P = 0.08) higher than Day two (1108±1142ml). Daily total fluid intake was not different (P = 0.27), averaging 6443±1941ml across both days. Core temperature and the time spent ≥ 70%HRmax were both elevated on Day one (when firefighters were not euhydrated). Firefighters' work activity profile was not different between both days of work. CONCLUSION: There was no difference in firefighters' pre- to post-shift hydration within each shift, suggesting ad libitum drinking was at least sufficient to maintain pre-shift hydration status, even in hot conditions. Firefighters' relative hypohydration on Day one (despite a slightly lower ambient temperature) may have been associated with elevations in core temperature, more time in the higher heart rate zones, and 'post-shift' RPE.

A kinematic based evaluation of upper extremity movement smoothness for tele-rehabilitation

Tele-rehabilitation has been widely studied in recent year, although a number of crucial issues has not been addressed. Quantitatively assessing exercise performance is vital in monitoring the progress in exercise based rehabilitation. This allows physiotherapists not only to refine rehabilitation plans, but also provides instant feedback to patients and facilitate the exercise performance in non-clinical setting. In this paper, we propose to evaluate the performance of upper extremity reaching tasks with in a kinematic perspective by assessing the smoothness of motion trajectories with the entropy of shape model, including curvature and torsion. The simulation result confirms that approximate entropy of shape model is consistent with the change of the smoothness in motion trajectory while it is capable of classifying six levels of the ability to perform upper extremity reaching tasks with higher accuracy.

Glucocorticoids enhance muscle endurance and ameliorate Duchenne muscular dystrophy through a defined metabolic program

Classic physiology studies dating to the 1930s demonstrate that moderate or transient glucocorticoid (GC) exposure improves muscle performance. The ergogenic properties of GCs are further evidenced by their surreptitious use as doping agents by endurance athletes and poorly understood efficacy in Duchenne muscular dystrophy (DMD), a genetic muscle-wasting disease. A defined molecular basis underlying these performance-enhancing properties of GCs in skeletal muscle remains obscure. Here, we demonstrate that ergogenic effects of GCs are mediated by direct induction of the metabolic transcription factor KLF15, defining a downstream pathway distinct from that resulting in GC-related muscle atrophy. Furthermore, we establish that KLF15 deficiency exacerbates dystrophic severity and muscle GC-KLF15 signaling mediates salutary therapeutic effects in the mdx mouse model of DMD. Thus, although glucocorticoid receptor (GR)-mediated transactivation is often associated with muscle atrophy and other adverse effects of pharmacologic GC administration, our data define a distinct GR-induced gene regulatory pathway that contributes to therapeutic effects of GCs in DMD through proergogenic metabolic programming.

Wearing a sports compression garment on the performance of visuomotor tracking following eccentric exercise : a pilot study

Clinical compression garments have been shown to improve functional control in patients with motor impairments, however, investigation in functional control has not been observed whilst wearing sports compression garments. This pilot study assessed motor control changes in the bicep brachii muscle following a bout of eccentric exercise designed to induce delayed onset muscle soreness for intervals up to 14 days after exercise. Eight male participants performed 35 maximal isokinetic eccentric extensions at 90° s−1. Participants where then randomly divided into one of two groups to perform a one-dimensional elbow flexion/extension visuomotor tracking task; one group wore a sports compression garment during the task, the other acted as control (no garment). The group who wore the compression garment performed the tracking task significantly better immediately post-exercise, and at days 1, 2 and 3 post-exercise (p ≤ 0.05). Non-significant but large and moderate effects sizes (ES), in tracking, were found between the two groups on day 5 (ES = 1.3) and day 7 (ES = 0.7), respectively. Further research is necessary to elucidate these preliminary findings, however, the results suggest that the wearing of sports compression garments post-eccentric exercise has a positive effect on functional motor control.

Effects of resistance exercise and fortified milk on skeletal muscle mass, muscle size, and functional performance in middle-aged and older men: an 18-mo randomized controlled trial

Limited data have suggested that the consumption of fluid milk after resistance training (RT) may promote skeletal muscle hypertrophy. The aim of this study was to assess whether a milk-based nutritional supplement could enhance the effects of RT on muscle mass, size, strength, and function in middle-aged and older men. This was an 18-mo factorial design (randomized control trial) in which 180 healthy men aged 50–79 yr were allocated to the following groups: 1) exercise + fortified milk, 2) exercise, 3) fortified milk, or 4) control. Exercise consisted of progressive RT with weight-bearing impact exercise. Men assigned to the fortified milk consumed 400 ml/day of low-fat milk, providing an additional 836 kJ, 1000 mg calcium, 800 IU vitamin D3, and 13.2 g protein per day. Total body lean mass (LM) and fat mass (FM) (dual-energy X-ray absorptiometry), midfemur muscle cross-sectional area (CSA) (quantitative computed tomography), muscle strength, and physical function were assessed. After 18 mo, there was no significant exercise by fortified milk interaction for total body LM, muscle CSA, or any functional measure. However, main effect analyses revealed that exercise significantly improved muscle strength (∼20–52%, P < 0.001), LM (0.6 kg, P < 0.05), FM (−1.1 kg, P < 0.001), muscle CSA (1.8%, P < 0.001), and gait speed (11%, P < 0.05) relative to no exercise. There were no effects of the fortified milk on muscle size, strength, or function. In conclusion, the daily consumption of low-fat fortified milk does not enhance the effects of RT on skeletal muscle size, strength, or function in healthy middle-aged and older men with adequate energy and nutrient intakes.

Amino acids and endurance exercise

Provides information on a study which examined the role of amino acids during endurance exercise and the implications for sports nutrition and performance. Description of amino acid utilization during exercise; Function of glutamine; Cardiovascular function of L-arginine.

Reliability of performance in repeated sprint cycling tests

We have estimated the reliability of performance in a commonly employed exercise test consisting of repeated sprints on a cycle ergometer. Eight recreationally active young men completed a practice trial and three more trials at 3- to 6-day intervals. Each trial consisted of two bouts of 30-s maximal-effort cycling on an electromagnetically braked cycle ergometer; the bouts were separated by 4 min of rest. The typical (standard) errors of measurement for peak and mean power between trials 2 to 4 were 2.5 and 1.7% respectively for the first bout and 1.9 and 1.8% for the second bout. These errors are substantially less than those in previous reliability studies of single 30-s sprint tests, probably because of differences in quality of ergometer. The typical errors for the difference between bouts (i.e., fatigue) for peak power and mean power were 3.0 and 2.5%, respectively. Typical errors for the average of the two bouts were 1.6 and 1.2% for peak and mean power respectively, which are small enough to give adequate precision for moderate treatment effects in studies with modest sample sizes.

Kim's style guide for the kinaesthetic boffin: an exercise in anti-communication

The following article refers to a performed paper, Did the Paradigm Shift for You, Darling? given as a collaboration between John Cumming, Yoni Prior, David Ritchie and me at the Double Dialogues Conference, Lines of Flight, at Theatreworks in Melbourne, November, 1997. The performance involved the staging of a mock analysis of a section of my choreographic work, Kim’s Style Guide for the Kinaesthetic Boffin, by three fictitious ‘critics’. The performance functioned as an implicit critique of three different approaches to interpreting dance. This article explores a theoretical position which supports that critique.