Max R. Paquette

Acute effects of barefoot, minimal shoes and running shoes on lower limb mechanics in rear and forefoot strike runners

Barefoot or minimal footwear running is currently a highly debated topic among runners and researchers. Several footwear companies have developed minimal running footwear to simulate barefoot running but few studies have compared minimal footwear to barefoot and shoes during running. The primary goal of this study was to compare acute changes in three-dimensional (3D) ground reaction forces (GRFs) and lower limb kinematics and kinetics of habitually shod rearfoot strike (RFS) and forefoot strike (FFS) runners between minimal shoes (MSH), barefoot and neutral cushion running shoes (SH). Lower extremity joint biomechanical variables of RFS and FFS runners were analysed using a 3D motion capture system and a force platform during overground running in barefoot, MSH and running shoes. Barefoot and MSH showed a more anterior foot strike than shoes. The loading rate of the impact peak GRF was greater in barefoot and MSH than in shoes. MSH showed greater ankle plantarflexor moment and negative power in early stance compared to shoes, which indicates greater eccentric plantarflexor muscle involvement in MSH than in shoes. Running shoes had greater peak knee extensor moment, early stance eccentric knee power and late stance concentric knee power compared to MSH and barefoot indicating less knee joint involvement. The current findings only pertain to acute changes between shoe conditions, and therefore training interventions in minimal footwear are warranted to further understand the adaptation effects of shod to barefoot or RFS to FFS running on lower limb biomechanics and running performance.

Effects of increased step width on frontal plane knee biomechanics in healthy older adults during stair descent.

BACKGROUND Peak internal knee abduction moment is a common surrogate variable associated with medial compartment knee loading. Stair descent has been shown to yield a greater peak knee abduction moment compared to level-walking. Changes in step width (SW) may lead to changes in frontal plane lower extremity limb alignment in the frontal plane and alter peak knee abduction moment. The purpose of this study was to investigate the effects of increased SW on frontal plane knee biomechanics during stair descent in healthy older adults. METHODS Twenty healthy adults were recruited for the study. A motion analysis system was used to obtain three-dimensional lower limb kinematics during testing. An instrumented 3-step staircase with two additional customized wooden steps was used to collect ground reaction forces (GRF) data during stair descent trials. Participants performed five stair descent trials at their self-selected speed using preferred, wide (26% leg length), and wider (39% leg length) SW. RESULTS The preferred normalized SW in older adults during stair descent was 20% of leg length. Wide and wider SW during stair descent reduced both first and second peak knee adduction angles and abduction moments compared to preferred SW in healthy adults. CONCLUSIONS Increased SW reduced peak knee adduction angles and abduction moments. The reductions in knee abduction moments may have implications in reducing medial compartment knee loads during stair descent.

Comparison of ankle kinematics and ground reaction forces between prospectively injured and uninjured collegiate cross country runners.

Biomechanical comparative studies on running-related injuries have included either currently or retrospectively injured runners. The purpose of this study was to prospectively compare ankle joint and ground reaction force variables between collegiate runners who developed injuries during the cross country season and those who did not. Running gait analyses using a motion capture system and force platform were conducted on 19 collegiate runners prior to the start of their cross country season. Ten runners sustained running-related injuries and 9 remained healthy during the course of the season. Strike index, peak loading rate of the vertical ground reaction force, dorsiflexion range of motion (ROM), eversion ROM, peak eversion angle, peak eversion velocity, and eversion duration from the start of the season were compared between injury groups. Ankle eversion ROM and peak eversion velocity were greater in uninjured runners while peak eversion angle was greater in injured runners. Greater ankle eversion ROM and eversion velocity with lower peak eversion angle may be beneficial in reducing injury risk in collegiate runners. The current data may only be applicable to collegiate cross country runners with similar training and racing schedules and threshold magnitudes of ankle kinematic variables to predict injury risk are still unknown.

Does increasing step width alter knee biomechanics in medial compartment knee osteoarthritis patients during stair descent

BACKGROUND Research shows that one of the first complaints from knee osteoarthritis (OA) patients is difficulty in stair ambulation due to knee pain. Increased step width (SW) has been shown to reduce first and second peak internal knee abduction moments, a surrogate variable for medial compartment knee joint loading, during stair descent in healthy older adults. This study investigates the effects of increased step width (SW) on knee biomechanics and knee pain in medial compartment knee OA patients during stair descent. METHODS Thirteen medial compartment knee OA patients were recruited for the study. A motion analysis system was used to obtain three-dimensional joint kinematics. An instrumented staircase was used to collect ground reaction forces (GRF). Participants performed stair descent trials at their self-selected speed using preferred, wide, and wider SW. Participants rated their knee pain levels after each SW condition. RESULTS Increased SW had no effect on peak knee abduction moments and knee pain. Patients reported low levels of knee pain during all stair descent trials. The 2nd peak knee adduction angle and frontal plane GRF at time of 2nd peak abduction moment were reduced with increasing SW. CONCLUSIONS The findings suggest that increases in SW may not influence knee loads in medial compartment knee OA patients afflicted with low levels of knee pain during stair descent.

Ankle and knee kinetics between strike patterns at common training speeds in competitive male runners

Abstract The purpose of this study was to investigate the interaction of foot strike and common speeds on sagittal plane ankle and knee joint kinetics in competitive rear foot strike (RFS) runners when running with a RFS pattern and an imposed forefoot strike (FFS) pattern. Sixteen competitive habitual male RFS runners ran at two different speeds (i.e. 8 and 6 min mile−1) using their habitual RFS and an imposed FFS pattern. A repeated measures analysis of variance was used to assess a potential interaction between strike pattern and speed for selected ground reaction force (GRF) variables and, sagittal plane ankle and knee kinematic and kinetic variables. No foot strike and speed interaction was observed for any of the kinetic variables. Habitual RFS yielded a greater loading rate of the vertical GRF, peak ankle dorsiflexor moment, peak knee extensor moment, peak knee eccentric extensor power, peak dorsiflexion and sagittal plane knee range of motion compared to imposed FFS. Imposed FFS yielded greater maximum vertical GRF, peak ankle plantarflexor moment, peak ankle eccentric plantarflexor power and sagittal plane ankle ROM compared to habitual RFS. Consistent with previous literature, imposed FFS in habitual RFS reduces eccentric knee extensor and ankle dorsiflexor involvement but produce greater eccentric ankle plantarflexor action compared to RFS. These acute differences between strike patterns were independent of running speeds equivalent to typical easy and hard training runs in competitive male runners. Current findings along with previous literature suggest differences in lower extremity kinetics between habitual RFS and imposed FFS running are consistent among a variety of runner populations.

Greater Step Widths Reduce Internal Knee Abduction Moments in Medial Compartment Knee Osteoarthritis Patients During Stair Ascent

Increased step widths have been shown to reduce peak internal knee abduction moments in healthy individuals but not in knee osteoarthritis patients during stair descent. This study aimed to assess effects of increased step widths on peak knee abduction moments and associated variables in adults with medial knee osteoarthritis and healthy older adults during stair ascent. Thirteen healthy older adults and 13 medial knee osteoarthritis patients performed stair ascent using preferred, wide, and wider step widths. Three-dimensional kinematics and ground reaction forces (GRFs) using an instrumented staircase were collected. Increased step width reduced first and second peak knee abduction moments, and knee abduction moment impulse. In addition, frontal plane GRF at time of first and second peak knee abduction moment and lateral trunk lean at time of first peak knee abduction moment were reduced with increased step width during stair ascent in both groups. Knee abduction moment variables were not different between knee osteoarthritis patients and healthy controls. Our findings suggest that increasing step width may be an effective simple gait alteration to reduce knee abduction moment variables in both knee osteoarthritis and healthy adults during stair ascent. However, long term effects of increasing step width during stair ascent in knee osteoarthritis and healthy adults remain unknown.

Effects of Footwear Condition on Maximal Jumping Performance

Abstract Harry, JR, Paquette, MR, Caia, J, Townsend, RJ, Weiss, LW, and Schilling, BK. Effects of footwear condition on maximal jumping performance. J Strength Cond Res 29(6): 1657–1665, 2015—The purpose of this investigation was to examine the effects of footwear on kinetics and lower extremity electromyographic (EMG) activity during the vertical jump (VJ) and standing long jump. Fifteen men performed the 2 jump types in 3 footwear conditions: barefoot, minimal shoes, and cross-training shoes. Jump displacement and kinetic data were collected, along with EMG activity of the biceps femoris, medial gastrocnemius, peroneus longus, semitendinosus/semimembranosus, soleus (SOL), tibialis anterior, vastus lateralis, and vastus medialis. Subjective footwear performance and comfort were also assessed with a custom survey. No differences were found in jump displacement, peak ground reaction forces (GRF), countermovement and propulsive phase durations, vertical impulse, peak countermovement, or average propulsive EMG activity. Significant differences in peak propulsive root mean square EMG were found between barefoot and minimal shoes (p = 0.030) and minimal shoes and shod (p = 0.031) conditions for the SOL during the VJ, and for average countermovement EMG of the semitendinosus/semimembranosus during the VJ between barefoot and shod (p = 0.039). Moderate-to-large effect sizes (>0.59) were found between conditions for horizontal GRF, propulsive phase duration, average EMG amplitude, and duration of EMG activity during the countermovement. Participants reported higher comfort ratings when shod compared with barefoot and minimal shoes for both jumps. Participants also perceived better performance when shod compared with barefoot and minimal shoes for the VJ only. No acute differences in displacement were observed between barefoot, minimal shoes, and cross-trainer shoes during vertical and horizontal jumps. Some differences in muscle activation and timing seem to be present, and thus, training effects between footwear conditions should be examined. Footwear familiarization may prove beneficial, as acute increases in comfort seem unrelated to performance improvements.

A kinematic method to detect foot contact during running for all foot strike patterns

The biomechanics of distance running are studied in relation to both understanding injury mechanisms and improving performance. Kinematic methods must be used to identify the stance phase of running when data are recorded during running on a standard treadmill or outside the laboratory. Recently, a focus on foot strike patterns has emerged in the field. Thus, there is a need for a kinematic method to identify foot contact that is equally effective for both rearfoot and non-rearfoot strike patterns. The purpose of this study was to determine whether a new kinematic method could accurately determine foot contact during running in both rearfoot and non-rearfoot strikers. Overground gait data were collected at on 22 runners, 11 with a rearfoot strike pattern and 11 with a non-rearfoot strike pattern. Data were processed to identify foot contact from: vertical ground reaction force, two previously published kinematic methods, and our new kinematic method. Limits of agreement were used to determine bias and random error of each kinematic method compared to ground reaction force onset. The new method had comparable random error at 200 Hz sampling frequency (5 ms per frame) to the previous methods (7 frames vs 6-9 frames) and produced the same offset for both strike patterns (3 frames), while the existing methods had different offsets for different strike patterns (4 or 7 frames). Study findings support use of this new method, as it can be applied to all running strike patterns without adjusting the frame offset, simplifying data processing.

Foot contact angle variability during a prolonged run with relation to injury history and habitual foot strike pattern.

Foot strike pattern and movement variability have each been associated with running injuries. Foot contact angle (FCA) is a common measure of strike pattern. Thus, variability in FCA could be an important running injury risk factor. The purposes of this study were to compare (a) foot contact angle (FCA) and its variability between runners with and without injury history and, (b) FCA variability between habitual rearfoot strike (RFS) and non‐RFS runners during a prolonged run. Twenty‐three runners with and 21 without injury history participated. Motion capture was used to collect kinematic data during a 40 min treadmill run. Average FCA and its variability were compared between injury groups and among four time points. FCA and its variability were not different between runners with and without injury history or among time points during the run. FCA variability was lower in non‐RFS compared to RFS runners (P < 0.001). Lower FCA variability in non‐RFS runners may have implications for higher injury risks due to repeated localized tissue loading. Prospective analyses on the effects of lower FCA variability on injury risk are needed.

Soreness-related changes in three-dimensional running biomechanics following eccentric knee extensor exercise

Abstract Runners often experience delayed onset muscle soreness (DOMS), especially of the knee extensors, following prolonged running. Sagittal knee joint biomechanics are altered in the presence of knee extensor DOMS but it is unclear how muscle soreness affects lower limb biomechanics in other planes of motion. The purpose of this study was to assess the effects of knee extensor DOMS on three-dimensional (3D) lower limb biomechanics during running. Thirty-three healthy men (25.8 ± 6.8 years; 84.1 ± 9.2 kg; 1.77 ± 0.07 m) completed an isolated eccentric knee extensor damaging protocol to elicit DOMS. Biomechanics of over-ground running at a set speed of 3.35 m s−1±5% were measured before eccentric exercise (baseline) and, 24 h and 48 h following exercise in the presence of knee extensor DOMS. Knee flexion ROM was reduced at 48 h (P = 0.01; d = 0.26), and peak knee extensor moment was reduced at 24 h (P = 0.001; d = 0.49) and 48 h (P < 0.001; d = 0.68) compared to baseline. Frontal and transverse plane biomechanics were unaffected by the presence of DOMS (P > 0.05). Peak positive ankle and knee joint powers and, peak negative knee joint power were all reduced from baseline to 24 h and 48 h (P < 0.05). These findings suggest that knee extensor DOMS greatly influences sagittal knee joint angular kinetics and, reduces sagittal power production at the ankle joint. However, knee extensor DOMS does not affect frontal and transverse plane lower limb joint biomechanics during running.