Higher midsole stack height changes the mechanical interface between foot and ground and therefore alters runner biomechanics over marathon distances. Research by Benno Nigg University of Calgary links greater cushioning and altered midsole geometry to changes in muscle work and perceived comfort. Thicker midsoles increase vertical compliance and can reduce instantaneous impact loading, but they also raise the foot relative to the ground, changing joint angles and lever arms across the ankle, knee, and hip.
Mechanical effects on stride
A higher stack tends to increase effective shoe compliance and can shift the center of pressure progression beneath the foot. That produces a longer moment arm at the ankle and can reduce required ankle dorsiflexor effort during early contact while increasing reliance on proximal musculature. Rodger Kram University of Colorado Boulder and collaborators have demonstrated that changes in sole construction, including added foam thickness and embedded plates, systematically affect running economy by altering how elastic energy is stored and returned across the limb. Individual responses vary widely; the same stack height that lowers metabolic cost for one runner can disrupt cadence or increase perceived instability for another.
Consequences for performance and injury risk
On long-distance running such as marathons, modest reductions in metabolic cost through optimized stack and midsole materials can translate into meaningful time savings for competitive athletes. However, thicker, more compliant soles also change load distribution. Reduced instantaneous ground impact may protect some tissues while increasing repetitive strain on others, especially the Achilles tendon and calf complex when ankle motion is constrained. Benno Nigg University of Calgary has emphasized that footwear-induced changes in neuromuscular demand can shift where injuries occur rather than eliminate them.
Cultural and territorial context matters: access to high-stack, high-tech footwear is uneven across countries and communities, which affects competitive fairness and local training adaptations. Environmental considerations are increasingly relevant because high-volume petroleum-derived foams and composite plates complicate recycling and generate different manufacturing footprints compared with traditional soles. Coaches, clinicians, and runners should therefore evaluate stack-height changes in the context of individual history, terrain, race goals, and broader social and environmental trade-offs.