Forefoot and rearfoot contributions to the lunge position in individuals with and without insertional Achilles tendinopathy

•Single-segment models of ankle dorsiflexion may overestimate rearfoot dorsiflexion in persons with Achilles tendon pain.•Greater forefoot dorsiflexion correlated with greater lunge test tibial inclination for participants with Achilles pain.•During evaluation and treatment, the lunge position may stress supporting structures of the medial longitudinal arch.

BackgroundClinicians use the lunge position to assess and treat restricted ankle dorsiflexion. However, the individual forefoot and rearfoot contributions to dorsiflexion and the potential for abnormal compensations are unclear. The purposes of this case–control study were to 1) compare single- (representing a clinical lunge position measure) versus multi-segment contributions to dorsiflexion, and 2) determine if differences are present in patients with tendinopathy.Methods32 individuals (16 with insertional Achilles tendinopathy and 16 age- and gender-matched controls) participated. Using three-dimensional motion analysis, the single-segment model was defined as tibial inclination relative to the whole foot. The multi-segment model consisted of rearfoot (tibia relative to calcaneus) and forefoot (1st metatarsal relative to calcaneus) motion. Two-way (kinematic model and group) analyses of variance were used to assess differences in knee bent and straight positions. Associations between models were tested with Pearson correlations.FindingsSingle-segment modeling resulted in ankle DF values 5° greater than multi-segment modeling that isolated rearfoot dorsiflexion for knee bent and straight positions (P < 0.01). Compared to controls, the tendinopathy group had 10° less dorsiflexion with the knee bent (P < 0.01). For the tendinopathy group, greater dorsiflexion was strongly associated with greater rearfoot (r = 0.95, P < 0.01) and forefoot (r = 0.81, P < 0.01) dorsiflexion. For controls, dorsiflexion was strongly associated with rearfoot (r = 0.87, P < 0.01) but not forefoot dorsiflexion (r = 0.23, P = 0.39).InterpretationClinically used single-segment models of ankle dorsiflexion overestimate rearfoot dorsiflexion. Participants with insertional Achilles tendinopathy may compensate for restricted and/or painful ankle dorsiflexion by increased lowering of the medial longitudinal arch (forefoot dorsiflexion) with the lunge position.