Adipose energy stores, physical work, and the metabolic syndrome: lessons from hummingbirds

Hummingbirds and other nectar-feeding, migratory birds possess unusual adaptive traits that offer important lessons concerning obesity, diabetes and the metabolic syndrome. Hummingbirds consume a high sugar diet and have fasting glucose levels that would be severely hyperglycemic in humans, yet these nectar-fed birds recover most glucose that is filtered into the urine. Hummingbirds accumulate over 40% body fat shortly before migrations in the spring and autumn. Despite hyperglycemia and seasonally elevated body fat, the birds are not known to become diabetic in the sense of developing polyuria (glucosuria), polydipsia and polyphagia. The tiny (3–4 g) Ruby-throated hummingbird has among the highest mass-specific metabolic rates known, and loses most of its stored fat in 20 h by flying up to 600 miles across the Gulf of Mexico. During the breeding season, it becomes lean and maintains an extremely accurate energy balance. In addition, hummingbirds can quickly enter torpor and reduce resting metabolic rates by 10-fold. Thus, hummingbirds are wonderful examples of the adaptive nature of fat tissue, and may offer lessons concerning prevention of metabolic syndrome in humans

np-elastic analyzing power A(N0) at 485 and 788 MeV

Journals published by the American Physical Society can be found at http://publish.aps.org/Measurements are reported for the np-elastic analyzing power from 30 degrees to 128 degrees c.m., at 485 and 788 MeV, with a typical precision of 0.005 and absolute accuracy of 2%. Results strengthen the isospin-0 phase-shift analysis, and clarify the absolute normalization of the polarized neutron beam and the isospin-0 inelasticity

The use of Traditional Medicine by Ghanaians in Canada

Peer reviewedPublisher PD

Locomotor changes in length and EMG activity of feline medial gastrocnemius muscle following paralysis of two synergists

The mechanism of the compensatory increase in electromyographic activity (EMG) of a cat ankle extensor during walking shortly after paralysis of its synergists is not fully understood. It is possible that due to greater ankle flexion in stance in this situation, muscle spindles are stretched to a greater extent and, thus, contribute to the EMG enhancement. However, also changes in force feedback and central drive may play a role. The aim of the present study was to investigate the short-term (1- to 2-week post-op) effects of lateral gastrocnemius (LG) and soleus (SO) denervation on muscle fascicle and muscle–tendon unit (MTU) length changes, as well as EMG activity of the intact medial gastrocnemius (MG) muscle in stance during overground walking on level (0%), downslope (−50%, presumably enhancing stretch of ankle extensors in stance) and upslope (+50%, enhancing load on ankle extensors) surfaces. Fascicle length was measured directly using sonomicrometry, and MTU length was calculated from joint kinematics. For each slope condition, LG-SO denervation resulted in an increase in MTU stretch and peak stretch velocity of the intact MG in early stance. MG muscle fascicle stretch and peak stretch velocity were also higher than before denervation in downslope walking. Denervation significantly decreased the magnitude of MG fascicle shortening and peak shortening velocity during early stance in level and upslope walking. MG EMG magnitude in the swing and stance phases was substantially greater after denervation, with a relatively greater increase during stance of level and upslope walking. These results suggest that the fascicle length patterns of MG muscle are significantly altered when two of its synergists are in a state of paralysis. Further, the compensatory increase in MG EMG is likely mediated by enhanced MG length feedback during downslope walking, enhanced feedback from load-sensitive receptors during upslope walking and enhanced central drive in all walking conditions

EFFECTS OF HONEST AND DISHONEST PRE-EXERCISE PLACEBO INGESTION ON VO2PEAK AND ISOMETRIC HANDGRIP PERFORMANCE

Jessica Moon1, Christian Espitia2, Landon Hiebert2, Christopher A. Fahs2, Lindy M. Rossow2 1Lindenwood University, St. Charles, Missouri; 2Lindenwood University-Belleville, Belleville Illinois Pre-exercise consumption of placebo has been shown to improve resistance and endurance exercise performance. However, the effects of placebo ingestion on graded exercise test performance have not been widely reported in the literature. PURPOSE: The purpose of this study was to examine the effects of honest (subjects were told they were consuming placebo) or dishonest (subjects were told they were consuming a pre-workout supplement) placebo ingestion on VO2peak values determined during a maximal treadmill graded exercise test. A secondary purpose of this study was to examine the effects of placebo consumption on isometric handgrip performance. We hypothesized that pre-exercise ingestion of both placebo conditions would result in increased VO2peak and handgrip performance compared to control. METHODS: 28 males (178.4 ± 6.94 cm, 83.3 ± 14.8 kg, 22.6 ± 2.3 yrs.) and 13 females (166.4 ± 8.49 cm, 73.6 ± 20 kg, 26.4 ± 11 yrs.) participated in this study. In a randomized, cross-over design, subjects performed treadmill VO2peak and isometric handgrip testing after consumption of honest placebo (HP) or dishonest placebo (DP). In addition, a third baseline trial (CON) was performed to establish performance values that were unaffected by a perceived placebo effect due to supplementation. All outcomes were assessed for normality using the Shapiro-Wilks test. When assumptions of normality were violated, log transformations were computed. However, transformations did not improve model assumptions. Therefore, non-transformed data is reported. One-way ANOVAs were used to analyze VO2peak and handgrip strength data across conditions. Alpha was set at 0.05 prior to all analyses. RESULTS: Significant between-groups differences (p \u3c 0.05) were not detected for relative VO2peak (CON = 46.2 ± 9.3 mL/kg/min; HP = 46.7 ± 10 mL/kg/min; DP = 46.6 ± 9.6 mL/kg/min) or for maximal handgrip strength (CON = 43 ± 9.6 kg; HP = 44.1 ± 12.4 kg; DP = 43.4 ± 12.1 kg). CONCLUSION: Administration of honest or dishonest placebo immediately prior to VO2peak and handgrip testing had no effect on performance compared to control. The VO2peak and isometric handgrip tests were found to be robust exercise tests not significantly influenced by perceived pre-workout supplement consumptio