In 10 consecutive patients with CECS, a 6-week forefoot strike running intervention led to decreased postrunning lower leg intracompartmental pressures. Pain and disability typically associated with CECS were greatly reduced for up to 1 year after intervention. Surgical intervention was avoided for all patients.

We studied the coordinated action of fingers during static tasks involving exertion of force and torque on a handheld object. Subjects were asked to keep a handle with an attachment that allowed for independent change of the suspended load (0.5-2.0 kg) and external torque (0.375-1.5 N m) in a vertical position while applying minimal effort. Normal and shear forces were measured from the thumb; normal forces only were measured from the four fingers.Experimental results-(1) the thumb shear force increased during supination efforts and decreased during pronation efforts; (2) the total moment of the normal finger forces only counterbalanced approximately 50% of the external torque, hence shear forces accounted for approximately one-half of the total torque exerted on the object; (3) the total normal force increased with external torque, and the total force magnitude did not depend on the torque direction; (4) the forces of the 'peripheral' (index and little) fingers depended mainly on the torque while the forces exerted by the 'central' (middle and ring) fingers depended both on the load and torque; (5) there was a monotonic relationship between the mechanical advantage of a finger (i.e., its moment arm during torque production) and the force produced by that finger; and (6) antagonist finger moments acting opposite to the intended direction of the total moment were always observed -at low torques the antagonist moments were as high as 40-60% of the agonist moments.Modeling-A three-zone model of coordinated finger action is suggested. In the first zone of load/ torque combinations, activation of antagonist fingers (i.e., fingers that generate antagonist moments) is necessary to prevent slipping. In the second zone, the activity of agonist fingers is sufficient for preventing slips. In the third zone, the performer has freedom to choose between either activating the antagonist fingers or redistributing activities amongst the agonist fingers. The findings of this study provide the foundation for neural network and optimization modeling described in the companion paper

The coordination of digits during combined force/torque production tasks was further studied using the data presented in the companion paper [Zatsiorsky et al. Biol Cybern this issue, Part I]. Optimization was performed using as criteria the cubic norms of (a) finger forces, (b) finger forces normalized with respect to the maximal forces measured in single-finger tasks, (c) finger forces normalized with respect to the maximal forces measured in a four-finger task, and (d) finger forces normalized with respect to the maximal moments that can be generated by the fingers. All four criteria failed to predict antagonist finger moments when these moments were not imposed by the task mechanics. Reconstruction of neural commands: The vector of neural commands c was reconstructed from the equation c=W(-1)F, where W is the finger interconnection weight matrix and F is the vector of finger forces. The neural commands ranged from zero (no voluntary force production) to one (maximal voluntary contraction). For fingers producing moments counteracting the external torque ('agonist' fingers), the intensity of the neural commands was well correlated with the relative finger forces normalized to the maximal forces in a four-finger task. When fingers produced moments in the direction of the external torque ('antagonist' fingers), the relative finger forces were always larger than those expected from the intensity of the corresponding neural commands. The individual finger forces were decomposed into forces due to 'direct' commands and forces induced by enslaving effects. Optimization of the neural commands resulted in the best correspondence between actual and predicted finger forces. The antagonist moments are, at least in part, due to enslaving effects: strong commands to agonist fingers also activated antagonist fingers.

The Broken Hill orebody, in Australia, is hosted in pelitic and psammitic gneisses that underwent metamorphism in the granulite facies. Peak metamorphism in the area occurred around 1600 Ma and exceeded temperatures of 850°C at pressures of 5-7 kilobars. The orebody is located in an area of intense deformation that occurred 5 to 15 million years after the peak metamorphism. Highly foliated pelitic schist directly adjacent to the Broken Hill orebody contains assemblages ranging from quartz -K-feldspar -biotite -garnet -sillimanite to quartz -muscovite -biotite -staurolite -garnet -chlorite. The latter assemblage equilibrated at temperatures as low as 600°C. Silicates in the low-temperature assemblages are intimately associated with galena that, in places contains clusters rich in Ag and Sb alloys, sulfides, and sulfosalts. One-bar experiments in the system Ag-Sb-S indicate that the assemblages seen in these rocks would have been molten at 500°C. These relations suggest that a polymetallic melt persisted at Broken Hill for up to twenty million years after peak metamorphism.Keywords: metamorphism, orebody, massive sulfides, melting, Broken Hill, Australia. SOMMAIRELe gisement de Broken Hill, en Australie, est situé dans un hôte gneissique métapélitique et métapsammitique qui a subi un métamorphisme au faciès granulite. Le paroxysme métamorphique dans la région a eu lieu il y a environ 1600 millions d'années, et a impliqué une température au delà de 850°C à une pression entre 5 et 7 kilobars. Le gisement est situé dans une zone de déformation intense active de 5 à 15 million d'années après la culmination métamorphique. Des schistes pélitiques fortement foliés directement adjacents au gisement de Broken Hill contiennent des assemblages allant de quartz -feldspath potassiquebiotite -grenat -sillimanite à quartz -muscovite -biotite -staurolite -grenat -chlorite. Ce deuxième assemblage s'est équilibré à une température aussi basse que 600°C. Les silicates des assemblages de plus faible température sont intimement associés à la galène qui, par endroits, contient des amas riches en alliages, sulfures et sulfosels d'argent et d'antimoine. Des expériences à un bar dans le système Ag-Sb-S indiquent que les assemblages de ces roches pourraient avoir été à l'état fondu à 500°C. Ces relations font penser qu'un liquide polymétallique a persisté à Broken Hill jusqu'à vingt millions d'années après la culmination métamorphique.(Traduit par la Rédaction)

There was an age-related increase in muscular effort during isometric elbow flexion and extension torque production tasks in healthy adults. Errors in muscular effort scaling exist, which increased as a function of both intensity (effort level) of motor task and age.