SummedDiffractionImagesSummed X-ray diffraction Images from the 5 points in the contraction cycleWorkLoopDataData generated from work-loops. In matrix "b" the columns are desingated as follows: column1=time, column2=force(voltage), column3=force(calibrated as Newtons), column4=length(voltage), column5=length(calibrated as meters), column6=actual length change (accounting for the displacement of the force transducer), column7=stimulus, column8=X-ray shutter signalxray_workloop_legendThis matrix identifies the Matlab work-loop file number with the moth number, temperature of the trial, and muscle location. Additionally it assigns the X-ray diffraction image number (0-4) with when in the contraction cycle the image was taken (represented as cycle fraction) since the X-ray shutter was triggered off of the stimulus signal.swounds.pyThis code opens the .npz files (compressed NumPy files). Use this code to access the summed X-ray diffraction images and find the intensity of the equatorial reflections.

Muscles not only generate force. They may act as springs, providing energy storage to drive locomotion. Although extensible myofilaments are implicated as sites of energy storage, we show that intramuscular temperature gradients may enable molecular motors (cross-bridges) to store elastic strain energy. Using time-resolved small-angle X-ray diffraction paired with in situ measurements of mechanical energy exchange in flight muscle of Manduca sexta we produced high-speed movies of X-ray equatorial reflections indicating cross-bridge association with myofilaments. A temperature gradient within the flight muscle leads to lower cross-bridge cycling in the cooler regions. Those cross-bridges could elastically return energy at the extrema of muscle lengthening and shortening, helping drive cyclic wing motions. These results suggest cross-bridges can perform functions other than contraction, acting as molecular links for elastic energy storage.