Lower Extremity Joint Loading Research Articles

Influence of Compliance and Aging of Artificial Turf Surfaces on Lower Extremity Joint Loading

Background: Artificial turf (AT) has been related to increased injury rates when compared to natural grass (NG). One potential reason for the differences in injury rates is the difference in mechanical characteristics of the surfaces. Over the course of a season on artificial turf, due to heavy use and environmental factors, properties of the surface (such as compliance) may be altered. The purpose was to compare the effects of newly installed versus aged AT on injury risks at the metatarsophalangeal, ankle, and knee joint during soccer-specific movements. Methods: Eleven male soccer players performed three movements on newly installed and ‘aged’ AT. Kinematics and kinetics were collected for the different surfaces. Results: Knee adduction moments were increased during the v-cut (119 Nm vs. 164 Nm, p = 0.02), and knee external rotation joint moments were increased during the circle run (23 Nm vs. 28 Nm, p = 0.04) with the aged surface. No surface effects were seen during the jog-sprint transition. Conclusions: For movements associated with a high risk for non-contact injuries, the age of the AT resulted in greater risk factors for injury potential at the knee joint. Further research comparing injury rates associated with AT should consider mechanical features, specifically surface compliance.

Effects Of Toe-in/ Out Toe-in Gait And Lateral Wedge Orthoses On Lower Extremity Joint Kinetics.

PURPOSE: The aim of the current investigation was to examine the effects of both lateral orthoses and toe-in/ toe-out foot progression angles on lower extremity joint loading during walking using a musculoskeletal simulation approach. METHODS: The current investigation examined 15 healthy males, walking in six different conditions (neutral, lateral orthoses, toe-in, lateral toe-in, toe-out and lateral toe-out). Walking kinematics were collected using an eight-camera motion capture system, and kinetics via an embedded piezoelectric force plate. Lower extremity joint loading was explored using a musculoskeletal simulation approach. RESULTS: This investigation showed that peak patellofemoral joint stress was greater in the neutral (3.96 KPa/BW) and lateral orthoses (4.20 KPa/BW) conditions compared to toe-in (3.33 KPa/BW), lateral toe-in (3.43 KPa/BW), toe-out (3.35 KPa/BW) and lateral toe-out (3.53 KPa/BW) and ankle joint impulse larger in the toe-in (1.65BW·s) and toe-out (1.62BW·s) foot progression angle modalities compared to neutral (1.51BW·s) and lateral orthoses (1.53BW·s). Furthermore, it was also shown that medial tibiofemoral impulse was statistically greater in the toe-in (1.20BW·s) and lateral toe-in (1.15BW·s) conditions compared to neutral (1.07BW·s), lateral orthoses (1.07BW·s), toe-out (1.09BW·s) and lateral toe-out (1.05BW·s). CONCLUSIONS: Therefore, the current investigation provides evidence that altering the foot progression angle may attenuate the risk from patellofemoral disorders whilst simultaneously enhancing the risk from degenerative ankle pathologies. Similarly, adopting a toe-in foot progression angle may also increase the risk from medial tibiofemoral degeneration.

Long-term donor-site morbidity after thumb reconstruction with twisted-toe technique.

Traumatic thumb loss is aserious injury affecting patient´sability to work and participate in activities of daily life. The main goal for aplastic surgeon is to restore hand grip, often by microsurgical methods. However, patients should be informed of all effects associated with tissue harvesting. The aim of the study was to assess the impact on donor foot and gait cycle in patients who have undergone thumb reconstruction using twisted-toe technique modified by Kempný. Twelve patients participated in the study: all suffered athumb loss between the years 2003 and 2011 and the twisted-toe technique for thumb reconstruction was utilized. The changes in foot pressure distribution and lower extremity joint loading were evaluated. The differences in total maximal plantar pressure, pressure time integral, contact area, and maximum force between the affected and non-affected foot were statistically significant (P 0.1). No significant differences of temporal gait parameters between the affected and non-affected extremity were observed; however, statistically significant differences in kinetics parameters, frontal ankle and knee moments were detected. Donor limb functionality and anatomical disability were assessed using pedobarography systems and 3D-gait analysis. The recorded differences in plantar pressure distribution (increased pressure in I., IV. and V. metatarsal areas) and overload of the medial compartment of the knee joint were the most significant findings. Therefore, wearing individually adapted shoe insoles as prevention of osteoarthrosis might be beneficial for patients after thumb reconstruction by atwisted-toe technique.

Effects of toe-in/ out toe-in gait and lateral wedge orthoses on lower extremity joint kinetics; an exploration using musculoskeletal simulation and Bayesian contrasts

IntroductionThe aim of the current investigation was to examine the effects of both lateral orthoses and toe-in/ toe-out foot progression angles on lower extremity joint loading during walking using a musculoskeletal simulation approach.MethodsThe current investigation examined 15 healthy males, walking in 6 different conditions (neutral, lateral orthoses, toe-in, lateral toe-in, toe-out and lateral toe-out). Walking kinematics were collected using an eight-camera motion capture system, and kinetics via an embedded piezoelectric force plate. Lower extremity joint loading was explored using a musculoskeletal simulation approach.ResultsThis investigation showed that peak patellofemoral joint stress was greater in the neutral (3.96 kPa/BW) and lateral orthoses (4.20 kPa/BW) conditions compared to toe-in (3.33 kPa/BW), lateral toe-in (3.43 kPa/BW), toe-out (3.35 kPa/BW) and lateral toe-out (3.53 kPa/BW) and ankle joint impulse larger in the toe-in (1.65BW·s) and toe-out (1.62BW·s) foot progression angle modalities compared to neutral (1.51BW·s) and lateral orthoses (1.53BW·s). Furthermore, it was also shown that medial tibiofemoral impulse was statistically greater in the toe-in (1.20BW·s) and lateral toe-in (1.15BW·s) conditions compared to neutral (1.07BW·s), lateral orthoses (1.07BW·s), toe-out (1.09BW·s) and lateral toe-out (1.05BW·s).Conclusions Therefore, the current investigation provides evidence that altering the foot progression angle may attenuate the risk from patellofemoral disorders whilst simultaneously enhancing the risk from degenerative ankle pathologies. Similarly, adopting a toe-in foot progression angle may also increase the risk from medial tibiofemoral degeneration.

Effects of running in minimal, maximal and traditional running shoes: a musculoskeletal simulation exploration using statistical parametric mapping and Bayesian analyses

The current study aimed to use a musculoskeletal simulation approach to examine running biomechanics in minimal, maximal and traditional running shoes using a concurrent SPM and Bayesian approach. Thirteen male participants ran over a force platform at 4.0 m/s in minimal maximal and traditional running shoes. Lower extremity joint loading and muscle forces were explored using a musculoskeletal simulation approach. Differences between conditions were examined using statistical parametric mapping (SPM) and Bayesian one-way repeated measures ANOVA. Bayesian analyses showed that traditional running shoes increased vastus intermedius (208.8BW·ms), vastus lateralis (320.2BW·ms) vastus medialis (188.7BW·ms), lateral tibiofemoral (495.9BW·ms) and patellofemoral joint stress (1683.4KPa/BW·s) integrals compared to minimal running shoes (185.0BW·ms, 281.9BW·ms, 167.2BW·ms, 456.5BW·ms & 1524.9KPa/BW·s). Furthermore, SPM showed that minimal footwear increased glutaeal, medial tibiofemoral and hip forces during the first 10% of the stance phase and Achilles tendon forces from 20 to 40% stance compared to traditional running shoes, whereas Bayesian analysis showed that minimal footwear increased loading rates (366.9BW/s) compared to maximal and traditional running shoes. (186.5BW/s) and traditional running shoes (161.5BW/s). Finally, SPM also showed that maximal footwear enhanced ankle eversion from 10 to 30% of stance compared to both minimal and traditional running shoes. This study therefore shows that minimal footwear may place runners at increased risk from impact related chronic injuries yet attenuate risk from patellofemoral and lateral tibiofemoral pathologies compared to traditional running shoes. In addition, owing to increases in ankle eversion, maximal running shoes may enhance risk to the aetiology of medial tibial stress syndrome compared to minimal and traditional running shoes.

Lower extremity joint loading during Bounce rope skip in comparison to run and walk

BackgroundBounce rope-skip holds immense scope as an aerobic exercise in space and time constrained urban setting with additional constraints placed by pandemic situations such as Covid 19, wherein adherence to commonly performed weight-bearing, aerobic activities like walking and running is a challenge. Limited knowledge informing biomechanical demands and misconceptions about knee joint loading, confines safe application of bounce rope-skip in health promotion. Thus, present study aimed to explore kinematics and lower-extremity joint loading during rope-skipping compared to walking and running. MethodsFollowing ethical approval, 3D motion analysis of bounce rope-skip, walk and run was captured from 22 healthy female participants aged 18–25yr using 12-camera Vicon system and 2AMTI force plates. Three trials for bounce rope-skip were recorded with five skip-jumps on force-plates at a cadence of 105 skips/min. Mid-skip, mid-gait and mid-run data were averaged to compute kinetic and kinematic variables for hip, knee and ankle during loading/initial contact, take-off/push-off and flight/mid-swing phases of rope-skip, walk and run. ResultAverage time of one rope-skip cycle was 1.2sec; mean foot contact time was 0.55sec and flight time was 0.65sec. In one bounce rope-skip cycle, hip motion ranged between 13.4o-35.3oflexion; knee between 13.6 o-67.9° flexion and ankle between 34.5odorsiflexion to-13.40plantarflexion. Vertical ground reaction force (vGRF) during rope-skip (landing-phase) was lower compared to run; however, it was higher than walk (p < 0.001). In coronal plane, peak hip and knee adductor moment during rope-skip were lower compared to run and higher than walk (p < 0.001). ConclusionBounce rope-skip generated low lower extremity joint loading compared to run; supporting its prescription as a hip and knee joint-protective aerobic weight-bearing exercise for health promotion in young adults.

Effects of running with minimal and conventional footwear in habitual and non-habitual users: a musculoskeletal simulation and statistical parametric mapping based approach

The current investigation examined running biomechanics in minimal and conventional footwear in two groups of runners who either ran habitually in minimal footwear (habitual minimal footwear users) or habitually in conventional footwear (non-habitual minimal footwear users). We studied ten male non-habitual minimal footwear users and ten male habitual minimal footwear users, who were required to complete ≥35 km per week of training. Lower extremity joint loading was explored using a musculoskeletal simulation approach. Differences between conditions were examined using statistical parametric mapping and 2 × 2 mixed ANOVA. This study revealed via the strike index that minimal footwear caused a more anterior contact position in both groups (habitual: minimal = 61.68% & conventional = 46.48%/non-habitual: minimal = 33.79% & conventional = 22.61%), although non-habitual runners still adopted a rearfoot strike pattern. In addition, in non-habitual users minimal footwear increased tibial accelerations (habitual: minimal = 6.35g & conventional = 7.06g/non-habitual: minimal = 9.54g & conventional = 8.16g), loading rates (habitual: minimal = 105.44 BW/s & conventional = 105.97 BW/s/non-habitual: minimal = 293.00 BW/s & conventional = 154.36 BW/s) and medial tibiofemoral loading rates (habitual: minimal = 196.17 BW/s & conventional = 274.96 BW/s/non-habitual: minimal = 274.96 BW/s & conventional = 212.57 BW/s). Furthermore, minimal footwear decreased patellofemoral loading in both habitual (minimal = 0.28BW·s & conventional = 0.31 BW·s) and non-habitual (minimal = 0.26 BW·s & conventional = 0.29 BW·s) users. Finally, Achilles tendon loading was larger in minimal footwear and in habitual runners (habitual: minimal = 0.79 BW·s & conventional = 0.71 BW·s/non-habitual: minimal = 0.71 BW·s & conventional = 0.65 BW·s) whereas iliotibial band strain rate was reduced in habitual (minimal = 28.32%/s & conventional = 30.30%/s) in relation to non-habitual (minimal = 42.96%/s & conventional = 42.87%/s) users. This study highlights firstly the importance of transitioning to minimal footwear and also indicates that post-transition may be effective in attenuating the biomechanical mechanisms linked to the aetiology of many chronic injuries.

Joint Contact Forces with Changes in Running Stride Length and Midsole Stiffness

The purpose of this study was to determine if lower extremity joint loading was influenced by stride length or shoe midsole cushioning. Ten subjects completed 10 trials of overground running at an average speed of 4.43 m/s in each of three conditions: normal running, running with a stride length (SL) reduced by 10% of normal, and running with a cushioned midsole stiffness (i.e., mechanical impact reduction of 13.7–10.9 g). Reaction forces calculated from inverse dynamics were summed with muscle forces estimated from a musculoskeletal model using static optimization to obtain joint contact forces at the hip, knee and ankle joints. Peak components of the contact forces [axial, anterior–posterior, and medial–lateral (ML)] were examined using parametric statistics (α = 0.05). Reducing stride length resulted in significant decreases in absolute peak ankle contact forces in the axial direction (normal: − 14.5 ± 1.5 BW; reduced SL: − 14.0 ± 1.6 BW) and the ML direction (normal: 0.67 ± 0.23 BW; reduced SL: 0.61 ± 0.21 BW). Reducing stride length also reduced the peak absolute axial forces at the knee (normal: − 10.6 ± 1.3 BW; reduced SL: − 9.8 ± 1.2 BW) and the hip (normal: − 7.26 ± 2.24 BW; reduced SL: − 6.75 ± 2.10 BW). The cushioned shoe did not statistically reduce the peak absolute contact forces from the normal stride condition at any of the joints. Post hoc stress analysis suggested that the observed changes in anterior hip force would increase stress more than any of the other statistically significant results. Reductions in stride length appear to decrease some joint contact variables but cushioning in the heel region of the shoe does not.

Biomechanical effects of a lightweight, sock-style minimalist footwear design during running: a musculoskeletal simulation and statistical parametric mapping approach

The aim of this study was to examine the effects of existing minimalist footwear, new sock-style minimalist footwear and conventional running footwear on lower extremity biomechanics, using a musculoskeletal simulation and statistical parametric mapping (SPM) approach. Thirteen male participants ran over an embedded force plate at 4.0 m/s, in (1) existing minimalist footwear, (2) new sock-style minimalist footwear and (3) conventional running shoes. Kinematics of the lower extremities was collected using an eight-camera motion analysis system and lower extremity joint loading was also explored using a musculoskeletal simulation approach. Differences between footwear conditions were examined using SPM and one-way repeated measures ANOVA. The strike index indicated that the foot contact position was significantly more anterior in existing minimalist footwear (44.19%) and new sock-style minimalist footwear (42.33%) compared to conventional running shoes (29.00%). The instantaneous loading rate was also significantly larger in existing minimalist footwear (271.68 BW/s) and new sock-style minimalist footwear (299.26 BW/s) in relation to conventional running shoes (122.48 BW/s). In addition, during the late stance phase compressive hip joint loading was significantly larger in both minimalist footwear. Similarly, Achilles tendon loading was statistically greater in both minimalist footwear compared to the conventional running shoe during the early and middle aspects of the stance phase. The observations from this analysis show that minimalist footwear may place non-habituated runners at greater risk from the mechanical factors linked to the aetiology of chronic lower limb running-related injuries.

Influence of the composition of artificial turf on rotational traction and athlete biomechanics

ABSTRACTArtificial turf advances have enabled surfaces to behave like natural grass, however, debate remains as to whether artificial turf is as safe as natural grass. To reduce injury risk, sport surfaces should have low rotational traction with artificial surfaces having a potential advantage as components can be manipulated to change surface properties and traction. The purpose of this study was to investigate the influence that different components of artificial turf have on rotational traction and athlete lower extremity joint loading. Twelve surfaces underwent mechanical testing to determine the influence of fibre density, fibre length, infill composition and compaction on rotational traction. Following mechanical testing, Control, Low and High Traction surfaces were selected for biomechanical analysis, where sixteen athletes performed maximum effort v-cuts while kinematic/kinetic data were recorded on each surface. Mechanically, fibre density, type of infill and compaction of the surface each independently influenced traction. The traction differences were substantial enough to alter the athlete kinematics and kinetics. Low traction surfaces reduced ankle and knee loading, while high traction surfaces increased ankle and knee loading . Reducing the rotational traction of sport surfaces is possible through alterations of individual components, which may reduce the joint loading at the knee and ankle joint.

Effects of different heel heights on lower extremity joint loading in experienced and in-experienced users: a musculoskeletal simulation analysis

This study examined the effects of different high-heeled footwear heights on lower extremity compressive joint loading and triceps-surae muscle–tendon kinematics during walking, using a musculoskeletal simulation-based approach, in both experienced and in-experienced high heel users. The current investigation examined 12 experienced and 12 in-experienced high-heel wearers, walking in four different footwear (high heel, medium heel, low heel, and trainer). Walking kinematics were collected using an eight-camera motion capture system and kinetics via an embedded force plate. Lower extremity joint loading and triceps-surae muscle kinematics were explored using a musculoskeletal simulation approach. Irrespective of experience, when wearing high heels of increasing height, compressive loading parameters at the medial tibiofemoral compartment and patellofemoral joint were significantly greater and exceeded the minimum clinically important difference (MCID). Furthermore, irrespective of wearers’ experience, the triceps-surae muscle–tendon units were placed in a shortened position when wearing high heels of increasing height, with the differences exceeding the MCID. It can be concluded that heeled footwear increases the mechanical factors linked to the aetiology of degenerative joint osteoarthritis and chronic shortening of the triceps-surae muscle–tendon units. Therefore, the current investigation provides evidence that irrespective of experience, heeled footwear of increasing height may negatively influence female’s lower extremity musculoskeletal health.

Acute effects of different orthoses on lower extremity kinetics and kinematics during running; a musculoskeletal simulation analysis

The current investigation aimed to examine the effects of different orthotic conditions on the biomechanical mechanisms linked to the aetiology of chronic pathologies using musculoskeletal simulation. 16 male and 20 females ran over an embedded force plate at 4.0 m/s, in five different conditions (medial, lateral, no-orthoses, semi-custom and off the shelf). Kinematics of the lower extremities were collected using an eight-camera motion capture system and lower extremity joint loading also explored using a musculoskeletal simulation approach. Differences between orthoses conditions were examined using 2 × 2 mixed ANOVA. External instantaneous load rate was significantly reduced in the off the shelf orthoses (male = 1290.60 and female = 1567.10 N/kg/s), compared to the medial (male = 1480.45 and female = 1767.05 N/kg/s) and semi-custom (male = 1552.99 and female = 1704.37 N/kg/s) conditions. In addition, peak patellofemoral stress was significantly lower in the off the shelf orthoses (male = 68.55 and female = 94.91 KPa/kg) compared to the lateral condition (male = 70.49 and female = 103.22 KPa/kg). Finally, peak eversion angles were significantly attenuated in the medial orthoses (male = -6.61 and female = -7.72 deg) compared to the lateral (male = -9.61 and female = -10.32 deg), no-orthoses (male = -8.22 and female = -10.10 deg), semi-custom (male = -8.25 and female = -9.49 deg) and off the shelf (male = -7.54 and female = -8.85 deg) conditions. The current investigation shows that different orthotic devices⁄ configurations may provide distinct benefits in terms of their effectiveness in attenuating the biomechanical parameters linked to the aetiology of chronic running injuries.

Effects of barefoot and shod running on lower extremity joint loading, a musculoskeletal simulation study

The aim of the current investigation was to utilize a musculoskeletal simulation-based approach, to examine the effects of barefoot and shod running on lower extremity joint loading during the stance phase. Twelve male runners, ran over an embedded force plate at 4.0 m/s, in both barefoot and shod conditions. Kinematics of the lower extremities were collected using an eight-camera motion capture system. Lower extremity joint loading was also explored using a musculoskeletal simulation and mathematical modelling approach, and differences between footwear conditions were examined using paired samples t tests. Peak Achilles tendon force was significantly larger (P = 0.039) when running barefoot (6.85 BW) compared to shod (6.07 BW). In addition, both medial (P = 0.013) and lateral (P = 0.007) tibiofemoral instantaneous load rates were significantly larger in the barefoot (medial 289.17 BW/s and lateral 179.59 BW/s) in relation to the shod (medial 167.57 BW/s and lateral 116.40 BW/s) condition. Finally, the barefoot condition (9.70 BW) was associated with a significantly larger (P = 0.037) peak hip force compared to running shod (8.51 BW). The current investigation indicates that running barefoot may place runners at increased risk from the biomechanical factors linked to the etiology of chronic lower extremity pathologies. However, future analyses using habitual barefoot runners, are required before more definitive affirmations regarding injury predisposition can be made.

Effects of Different Gait Cadences on Lower Extremity Joint Loading during Stair Descent in Obese Children

IThe purpose of this study was to examine the effects of different gait cadences on lower extremity joint loading during stair descent in obese children. Twelve obese children (age = 12.0 ± 0.2 years, BMI = 30.07 ± 2.10 kg/m^2) and 12 non-obese children (age = 12.0 ± 0.2 years, BMI = 17.38 ± 1.32 kg/m^2) were recruited as the participants in this study. All participants were performed a stair descent task under four different conditions of gait cadences (self-paced, 60, 90 and 120 steps/min). A mega high-speed camera synchronized with an ATMI force plate was used to collect data during the landing phase of stair descent. The Kwon 3D and DASYLab 6.0 software were applied to analyze the kinematic data, ground reaction force and center of pressure. The joint moment, joint work and joint power of lower limb were calculated by the inverse dynamics method. Results indicated an interaction between group and gait cadences in negative work of the ankle joint. The obese group demonstrated a greater negative work of the ankle joint at 60 and 90 steps/min conditions than 120 steps/min and self-paced conditions. While walking at the speed of 60 and 90 steps/min, the obese group showed a larger negative work of the ankle joint compared to the non-obese group. Furthermore, the obese group demonstrated a smaller positive work of the hip joint than the non-obese group. These findings indicate that children’s body mass influences their gait cadences during stair descent. Obese children increase the risk for lower-extremity joint injury during the stair descent at lower cadences due to a weaker capacity of gait compensation that is resulting from more negative work at the ankle joint and less positive work at the hip joint.

The effect of translational and rotational traction on lower extremity joint loading

Previous studies have linked footwear traction to lower extremity non-contact injury; however, these studies mainly focussed on rotational traction exclusively. While studies have shown that increases in traction lead to increases in joint loading, represented by joint moments, these studies failed to determine how the individual components of rotational and translational traction affect joint loading. Therefore, this study investigated how each component of traction independently affects lower extremity joint loading. Traction testing was performed using a robotic testing machine on three shoes that had independent alterations of translational and rotational traction. All testing was conducted on a sample piece of artificial turf. Kinematic and kinetic data were then collected on 10 athletes performing two cutting movements in each shoe condition. As rotational and translational traction were independently altered, decreased rotational traction led to significant decreases in transverse and frontal plane joint loading at the ankle and knee joints, while increases in translational traction led to increases in frontal plane joint loading at the ankle and knee joints. Increases in joint loading in the transverse and frontal planes are one of the possible mechanisms of lower extremity non-contact injury. Both translational and rotational traction can independently alter the joint loading.

The Effects of Footwear on Lower Extremity Joint Loading: A Literature Review

The Effects of Footwear on Lower Extremity Joint Loading: A Literature Review

Lower extremity joint loading during level walking with Masai barefoot technology shoes in overweight males

The purpose of this study was to evaluate the effects of Masai barefoot technology (MBT) shoes on lower extremity joint loading in overweight males during level walking. Therefore, lower extremity kinematics, kinetics, and muscle electromyographic signals of the vastus lateralis (VL), biceps femoris (BF), and gastrocnemius medialis (GM) were recorded in 10 overweight males at a self-chosen walking speed with MBT shoes and conventional shoes. Selected peak joint moments, maximal joint force loading rates, mean muscle intensities, and co-activation indices of the VL/BF, as well as of the VL/GM were analyzed and compared for the two shoe conditions using paired Student's t-tests (α=0.05). Results showed that walking with MBT shoes reduced first peak knee adduction moments in overweight subjects. During midstance and terminal stance, increases in VL/GM co-activation, accompanied by increases in VL and GM (only terminal stance) intensities were found for the MBT situation. Kinetic variables analyzed to assess ankle and hip joint loading did not exhibit any statistical differences. These results suggest that using MBT shoes diminishes medial compartment loads at the knee without overloading hip or ankle joints in overweight males. However, the additional muscle loading should not be overlooked, and warrants further investigation.

Footwear Traction and Lower Extremity Joint Loading

Background: Traction is influenced by the sole architecture and playing surface, with increases in traction potentially leading to injury. The mechanism as to how or why increased traction could lead to injury remains unknown. Purpose: This study was undertaken to determine how shoes of different sole designs and traction influence knee and ankle joint moments. Study Design: Controlled laboratory study. Methods: Traction testing was performed on 2 shoes of varying sole designs (tread vs smooth) using a robotic testing machine. All testing was conducted on a 60-cm × 90-cm piece of sample track surface. Kinematic and kinetic data were then collected on 13 recreational athletes performing running V-cuts in the 2 different shoe conditions. Five trials per condition were collected with reflective markers placed on the right shank and shoe of each participant. Kinematic and kinetic data were collected using an 8–high-speed camera system and force plate. Results: The coefficient of translational traction and the peak moment of rotation were both significantly higher in the tread shoe compared with the smooth shoe (1.00 vs 0.87 and 23.87 N·m vs 16.12 N·m, respectively). The high-traction shoe had significantly higher peak ankle external rotation moments (89.58 N·m vs 80.17 N·m), peak knee external rotation moments (36.23 N·m vs 32.02 N·m), peak knee adduction moments (224.0 N·m vs 186.8 N·m), and knee adduction angular impulse (2.10 Nms vs 1.83 Nms) compared with the low-traction shoe. Conclusion: Increased shoe traction significantly increased ankle and knee joint moments during a V-cut. Despite the significant difference in traction, no difference in performance was observed. These changes could have an effect on ankle and knee joint injury. Clinical Relevance: Shoes with decreased traction could be used in sports to reduce the joint moments in the knee and ankle and potentially reduce injury without a loss in performance.

Lower extremity joint loading in level and graded walking

Lower extremity joint loading in level and graded walking

Walking

Lower extremity joint loading during walking is strongly affected by the steepness of the slope and might cause pain and injuries in lower extremity joint structures. One feasible measure to reduce joint loading is the reduction of walking speed. Positive effects have been shown for level walking, but not for graded walking or hiking conditions. The aim of the study was to quantify the effect of walking speed (separated into the two components, step length and cadence) on the joint power of the hip, knee and ankle and to determine the knee joint forces in uphill and downhill walking. Ten participants walked up and down a ramp with step lengths of 0.46, 0.575 and 0.69 m and cadences of 80, 100 and 120 steps per minute. The ramp was equipped with a force platform and the locomotion was filmed with a 60 Hz video camera. Loading of the lower extremity joints was determined using inverse dynamics. A two‐dimensional knee model was used to calculate forces in the knee structures during the stance phase. Walking speed affected lower extremity joint loading substantially and significantly. Change of step length caused much greater loading changes for all joints compared with change of cadence; the effects were more distinct in downhill than in uphill walking. The results indicate that lower extremity joint loading can be effectively controlled by varying step length and cadence during graded uphill and downhill walking. Hikers can avoid or reduce pain and injuries by reducing walking speed, particularly in downhill walking.