The effect of textured insoles on kinetics and kinematics of overground running was assessed. 16 male injury-free-recreational runners attended a single visit (age 23 ± 5 yrs; stature 1.78 ± 0.06 m; mass 72.6 ± 9.2 kg). Overground 15-m runs were completed in flat, canvas plimsolls both with and without textured insoles at self-selected velocity on an indoor track in an order that was balanced among participants. Average vertical loading rate and peak vertical force (F) were captured by force platforms. Video footage was digitised for sagittal plane hip, knee and ankle angles at foot strike and mid stance. Velocity, stride rate and length and contact and flight time were determined. Subjectively rated plantar sensation was recorded by visual scale. 95% confidence intervals estimated mean differences. Smallest worthwhile change in loading rate was defined as standardised reduction of 0.54 from a previous comparison of injured versus non-injured runners. Loading rate decreased (-25 to -9.3 BW s; 60% likely beneficial reduction) and plantar sensation was increased (46-58 mm) with the insole. F (-0.1 to 0.14 BW) and velocity (-0.02 to 0.06 m s) were similar. Stride length, flight and contact time were lower (-0.13 to -0.01 m; -0.02 to-0.01 s; -0.016 to -0.006 s) and stride rate was higher (0.01-0.07 steps s) with insoles. Textured insoles elicited an acute, meaningful decrease in vertical loading rate in short distance, overground running and were associated with subjectively increased plantar sensation. Reduced vertical loading rate could be explained by altered stride characteristics.

ance-running specialists [1-3]. However, injury rates ranging from 20-79% [4-6] suggest modern humans are prone to injury in running which the Endurance-Running hypothesis contends is a species-specific movement pattern for which we are well adapted. Explanations and solutions focus largely on shoe design and gait mechanics. Foot structure and function, in contrast, have received little attention in running-related research [7]. Moreover, and despite continued interest in running-shoe design, there has been little attention on how footwear might influence foot structure and function and therefore the rest of the kinetic chain above it. This opinion piece addresses these issues and proposes a novel perspective that could add to factors explaining injury risk in endurance running. Endurance-Running Hypothesis The fossil record of the genus homo shows evidence of musculoskeletal adaptations that reduce the mechanical and energetic demands of bipedal-endurance running. Adaptations differentiating homo sapiens from early homo and from primate ancestors include the nuchal ligament for head stabilisation, a mobile thoracic spine permitting counter rotation of the trunk and legs, long legs that lengthen the stride so reducing energy cost per unit of distance, large proximal hip muscles (gluteals) to control forward pitch of the torso at ground contact, long Achilles tendons and plantar arches to facilitate energy storage and return, and short-straight toes that minimise toe flexion moments and smooth the forward trajectory of body weight over the supporting foot [1-3]. Many of these adaptations benefit running only, suggesting that

2021) Differences in stride length and lower limb moments of recreational runners during over-ground running while barefoot, in minimalist and in maximalist running shoes. Footwear Science, 13 (2). pp. 133-141.

The absence of a systematic reduction in Injury frequency, despite decades of research has led to suggestions that the scientific method has been unsuccessful in resolving the problem of running injuries [3][4][5][6]. The Problem: Running Injury Statistics in the Past 40 Years are UnchangedRunning for recreation first became very popular in the1970s [7] and was followed soon after by studies on the prevalence of injuries in runners. Results of these studies varied, with injury incidence ranging between 15% and 85% [8-27] (Figure 1). However, there seems to be noapparent systematic change in injury incidence over time. Changes in the running populationThe runners in the 1970s and 1980s were different to the runners in the current millennium. The participants captured by studies performed in the 1970s and 1980s were dedicated runners, aiming to win, lean, primarily just trained by running, were mostly (75%) male [19], and were around mid thirties in age [8,12,15,19,26]. The runners in more recent studies are primarily recreational, running a marathon with the goal to simply finish, often overweight, often involved in cross-training activities in addition to running, and are around mid forties in age [9,10,24]. The majority of runners are also now female (54%). The populations studied in various epidemiological investigations also differ, with some comprising novice runners and others comprising competitive runners [10,23,24]. These differences in the populations studied confound injury frequency Current OpiniOnCheck for updates

ance-running specialists [1-3]. However, injury rates ranging from 20-79% [4-6] suggest modern humans are prone to injury in running which the Endurance-Running hypothesis contends is a species-specific movement pattern for which we are well adapted. Explanations and solutions focus largely on shoe design and gait mechanics. Foot structure and function, in contrast, have received little attention in running-related research [7]. Moreover, and despite continued interest in running-shoe design, there has been little attention on how footwear might influence foot structure and function and therefore the rest of the kinetic chain above it. This opinion piece addresses these issues and proposes a novel perspective that could add to factors explaining injury risk in endurance running. Endurance-Running Hypothesis The fossil record of the genus homo shows evidence of musculoskeletal adaptations that reduce the mechanical and energetic demands of bipedal-endurance running. Adaptations differentiating homo sapiens from early homo and from primate ancestors include the nuchal ligament for head stabilisation, a mobile thoracic spine permitting counter rotation of the trunk and legs, long legs that lengthen the stride so reducing energy cost per unit of distance, large proximal hip muscles (gluteals) to control forward pitch of the torso at ground contact, long Achilles tendons and plantar arches to facilitate energy storage and return, and short-straight toes that minimise toe flexion moments and smooth the forward trajectory of body weight over the supporting foot [1-3]. Many of these adaptations benefit running only, suggesting that