Post-marathon wearing of Masai Barefoot Technology shoes facilitates recovery from race-induced fatigue: an evaluation utilizing a visual analog scale

Purpose

To investigate the potential benefit of post-race wearing of unstable shoes (Masai Barefoot Technology [MBT]) on recovery from marathon race–induced fatigue.

Patients and methods

Forty-five runners who participated in a full marathon race were divided into three groups: 1) MBT shoes, 2) trail running shoes, and 3) control (CON). Participants ran a full marathon with their own running shoes, and then put on the assigned shoes immediately after the race. They continued to wear the assigned shoes for the ensuing 3 days. The CON group wore their usual shoes. Estimates of post-race fatigue were made by the participants on questionnaires that utilized a visual analog scale. Estimates were made just after the race, as well as for the next 3 days.

Results

The subjective fatigue of the MBT group was lower than that of the CON (P<0.05) or trail running shoe groups (P<0.05) on day 3.

Conclusion

MBT shoe intervention can promote recovery from the fatigue induced by running a full marathon.

Ipsilateral wrist-ankle movements in the sagittal plane encoded in extrinsic reference frame

When performing oscillatory movements of two joints in the sagittal plane, there is a directional constraint for performing such movements. Previous studies could not distinguish whether the directional constraint reflected movement direction encoded in the extrinsic (outside the body) reference frame or in the intrinsic (the participants' torso/head) reference frame since participants performed coordinated movements in a sitting position where the torso/head was stationary relative to the external world. In order to discern the reference frame in the present study, participants performed paced oscillatory movements of the ipsilateral wrist and ankle in the sagittal plane in a standing position so that the torso/head moved relative to the external world. The coordinated movements were performed in one of two modes of coordination, moving the hand upward concomitant with either ankle plantarflexion or ankle dorsiflexion. The same directional mode relative to extrinsic space was more stable and accurate as compared with the opposite directional mode. When forearm position was changed from the pronated position to the supinated position, similar results were obtained, indicating that the results were independent of a particular coupling of muscles. These findings suggest that the directional constraint on ipsilateral joints movements in the sagittal plane reflects movement direction encoded in the extrinsic reference frame.

Programmed death-1 promotes tolerance by blocking the T cell receptor-induced stop signal. (167.26)

Programmed death-1 (PD-1) and CTLA-4 are inhibitory receptors expressed on activated T cells that are critical for preventing autoimmunity. However, the biological context in which PD-1 and CTLA-4 control T cell tolerance is not fully understood. In this study we used an antigen specific diabetes model and T cell dynamic motility during the induction and maintenance of tolerance in vivo by two-photon imaging. Using this system we demonstrate that unlike naive or activated islet antigen-specific T cells, tolerized islet antigen-specific T cells moved freely and did not swarm around antigen-bearing dendritic cells (DCs) in pancreatic lymph nodes. However, blocking interactions between PD-1 and PD-L1 altered the dynamic T cell motility and caused the breakdown in peripheral tolerance resulting in autoimmune diabetes. Neutralizing CTLA-4, on the other hand, did not impact tolerized T cell motility in vivo or clinical disease. The ability of PD-1 to influence the T-cell stop signal was antigen dependent, since T cell motility and T cell-DC contact times were unaffected by PD-L1 neutralization in non-draining (inguinal) LNs. These data provide in vivo evidence that PD-1 -PD-L1 interactions are critical for the maintenance of peripheral tolerance and prevention of autoimmunity. Further, the effects of PD-1 are fundamentally distinct from those of CTLA-4 and suggest unique mechanisms of action for these two inhibitory receptors.

Interactions between PD-1 and PD-L1 promote tolerance by blocking the TCR-induced stop signal

Programmed death 1 (PD-1) is an inhibitory molecule expressed on activated T cells; however, the biological context in which PD-1 controls T cell tolerance remains unclear. Using two-photon laser-scanning microscopy, we show here that unlike naive or activated islet antigen-specific T cells, tolerized islet antigen-specific T cells moved freely and did not swarm around antigen-bearing dendritic cells (DCs) in pancreatic lymph nodes. Inhibition of T cell antigen receptor (TCR)-driven stop signals depended on continued interactions between PD-1 and its ligand, PD-L1, as antibody blockade of PD-1 or PD-L1 resulted in lower T cell motility, enhanced T cell-DC contacts and caused autoimmune diabetes. Blockade of the immunomodulatory receptor CTLA-4 did not alter T cell motility or abrogate tolerance. Thus, PD-1-PD-L1 interactions maintain peripheral tolerance by mechanisms fundamentally distinct from those of CTLA-4.