Before revision:  Akin to ``breathing,'' convective-diffusive transport in sarcomeres is sufficient to promote metabolite exchange , and may play a role in the regulation of contraction itself.
After revision:  Volume change and advective solute transport varies with the phase of muscle stimulation during periodic contraction but remains significant at all conditions. Nonetheless, advective transport varies will occur in all cases where the sarcomere is not isovolumetric. Akin to "breathing," advective-diffusive transport in sarcomeres is sufficient to promote metabolite exchange , and may play a role in the regulation of contraction itself.