Elizabeth J. Durden-Myers, Margaret E. Whitehead and Niek Pot
nurturing human flourishing. Therefore, the aim of this paper is to discuss the relationship between physical literacy and human flourishing in detail, unveiling what value this connection may hold in promoting physical literacy as an element integral in achieving a full and flourishing life. Human
Thomas Haugen, Gøran Paulsen, Stephen Seiler and Øyvind Sandbakk
Higher, faster, stronger: what are the upper limits of human performance? In a published study from January 2008, Berthelot et al 1 estimated that world records had reached 99% of its asymptotic values and that human upper performance limits in sport would be reached within 1 generation. Only
Samantha L. Winter and John H. Challis
For a physiologically realistic joint range of motion and therefore range of muscle fiber lengths, only part of the whole muscle force-length curve can be used in vivo; that is, only a section of the force-length curve is expressed. Previous work has determined that the expressed section of the force-length curve for individual muscles can vary between subjects; however, the degree of intersubject variability is different for different muscles. This study determined the expressed section of both the rectus femoris and gastrocnemius—muscles with very different ratios of tendon slack length to muscle fiber optimum length—for 28 nonspecifically trained subjects to test the hypothesis that the value of this ratio affects the amount of variability in the expressed section. The force-length curves of the two muscles were reconstructed from moment-angle data using the method of Herzog & ter Keurs (1988). There was no relationship between the expressed sections of the force-length curve for the two muscles. Less variability was found in the expressed section of the gastrocnemius compared with the rectus femoris, supporting the hypothesis. The lack of relationship between the expressed sections of the two muscles has implications for motor control and for training muscle for rehabilitation.
Kristen E. Thomas and Leah R. Bent
The integration of vestibular and somatosensory information for the control of lower limb musculature remains elusive. To determine whether a subthreshold vestibular input influences the cutaneous evoked response, the isometric EMG activity in the posturally inactive soleus muscles of 13 healthy, seated subjects was collected. Vestibular afferents were activated using galvanic vestibular stimulation (GVS; 1.8–2.5mA, 500ms), while percutaneous electrical stimulation was delivered to the distal tibial nerve (11ms train of 3 × 1.0 ms pulses, 200Hz) to activate foot sole skin afferents. GVS elicited responses in soleus both independently and when combined with cutaneous stimulation. The responses to the combined sensory input showed an interaction between the two sensory modalities to influence muscle activation. Of note is the presence of significant muscle modulation in the combined condition, where subthreshold vestibular inputs altered the outcome of the cutaneous reflex response. This finding has implications for individuals with sensory deficiency. In the case of an absent or deficient sensory modality, balance protective reflexes to maintain postural equilibrium may be enhanced with targeted sensory augmentation.
Christopher M. McLeod and Calvin Nite
currently unable to account for markets depending on exceptional human performance, like sport markets. Therefore, a theory is needed that can account for human capital ecosystems . In a human capital ecosystem, actors are responsible for investing in and capturing returns from human capital. The purpose
Marc Monsour, Tanya D. Ivanova, Tim D. Wilson and S. Jayne Garland
The purpose of this study was to investigate whether application of bipolar galvanic vestibular stimulation (GVS) would influence the common modulation of motor unit discharge rate in bilateral soleus muscles during quiet standing. Soleus motor unit activity was recorded with fine wire electrodes in each leg. Subjects stood, with eyes closed, on two adjacent force platforms to record postural sway with the head facing straight ahead, turned to right, or turned left. Subjects also swayed voluntarily without GVS to the same position as evoked during the GVS. There was no difference in the common drive to bilateral soleus motoneurons during quiet standing and voluntary sway tasks. Common drive was significantly lower during right cathode GVS with the head straight or turned to the right. These results demonstrate that manipulation of vestibular afferent input influences the common modulation of bilateral soleus motor unit pairs during quiet standing.
Neil Chapman, John Whitting, Suzanne Broadbent, Zachary Crowley-McHattan and Rudi Meir
electrically stimulated in vivo human muscle. 23 However, it is important to note an apparent disparity in magnitude of RFE between electrically stimulated and voluntarily activated contractions. In fact, the magnitude of RFE has been found to vary greatly in vivo voluntarily contracted human muscle. 23
Scott W. Ducharme and Richard E.A. van Emmerik
Biological systems are inherently variable, and this variability has been the focus of much research in the movement sciences. In human locomotion research, a commonly accepted convention has been that variability is a one-size-fits-all parameter; more is bad. This “negative” perspective towards
Bradley D. Hatfield, Calvin M. Lu and Jo B. Zimmerman
was the “Optimization of Human Performance,” and 13 scholars who are internationally recognized leaders in kinesiology and beyond presented their views on this topic from multiple perspectives spanning the historical and philosophical to the biophysical and sports-medicine dimensions. We now present