Ankle Kinetics Research Articles

The ankle dorsiflexion kinetics demand to increase swing phase foot-ground clearance: implications for assistive device design and energy demands

BackgroundThe ankle is usually highly effective in modulating the swing foot’s trajectory to ensure safe ground clearance but there are few reports of ankle kinetics and mechanical energy exchange during the gait cycle swing phase. Previous work has investigated ankle swing mechanics during normal walking but with developments in devices providing dorsiflexion assistance, it is now essential to understand the minimal kinetic requirements for increasing ankle dorsiflexion, particularly for devices employing energy harvesting or utilizing lighter and lower power energy sources or actuators.MethodsUsing a real-time treadmill-walking biofeedback technique, swing phase ankle dorsiflexion was experimentally controlled to increase foot-ground clearance by 4 cm achieved via increased ankle dorsiflexion. Swing phase ankle moments and dorsiflexor muscle forces were estimated using AnyBody modeling system. It was hypothesized that increasing foot-ground clearance by 4 cm, employing only the ankle joint, would require significantly higher dorsiflexion moments and muscle forces than a normal walking control condition.ResultsResults did not confirm significantly increased ankle moments with augmented dorsiflexion, with 0.02 N.m/kg at toe-off reducing to zero by the end of swing. Tibialis Anterior muscle force incremented significantly from 2 to 4 N/kg after toe-off, due to coactivation with the Soleus. To ensure an additional 4 cm mid swing foot-ground clearance, an estimated additional 0.003 Joules/kg is required to be released immediately after toe-off.ConclusionThis study highlights the interplay between ankle moments, muscle forces, and energy demands during swing phase ankle dorsiflexion, offering insights for the design of ankle assistive technologies. External devices do not need to deliver significantly greater ankle moments to increase ankle dorsiflexion but, they should offer higher mechanical power to provide rapid bursts of energy to facilitate quick dorsiflexion transitions before reaching Minimum Foot Clearance event. Additionally, for ankle-related bio-inspired devices incorporating artificial muscles or humanoid robots that aim to replicate natural ankle biomechanics, the inclusion of supplementary Tibialis Anterior forces is crucial due to Tibialis Anterior and Soleus co-activation. These design strategies ensures that ankle assistive technologies are both effective and aligned with the biomechanical realities of human movement.

Effect of ball positions on trunk, hip, knee, and ankle joint kinematics and kinetics during a spike jump in volleyball

BackgroundAnterior cruciate ligament injuries are serious conditions encountered in volleyball players and occur frequently during spike jump landings. During spike jumps, the lower limb kinematics and kinetics during landing may be altered in relation to the ball position. Research questionDoes the ball position have an effect on lower-limb kinematics and kinetics during spike jumps? MethodsWe measured the lower limb kinematics and kinetics of 20 healthy female college volleyball athletes during a spike jump using a three-dimensional motion analysis system. The ball positions were set to normal, dominant, and non-dominant positions. A repeated analysis of variance was used to compare the lower limb kinematics and kinetics at the initial contact and the maximum knee flexion during jump landing. Additionally, statistical parametric mapping analysis was used to analyze changes over time during the spike jumps. ResultsAt the initial contact of the spike jump landing, the knee valgus angle, trunk lateral bending angle, and maximum knee valgus moment when the ball was set at the non-dominant position increased compared to those at the dominant position. Statistical parametric mapping analysis showed no significant change in knee valgus angle and moment of jump landing. ConclusionKnee valgus angle, trunk lateral bending angle, and maximum knee valgus moment increased with the non-dominant position; furthermore, the risk of ACL injury may also be increased. SignificanceThe posture at ball impact may influence the landing kinematics and kinetics. Therefore, it is necessary to pay close attention to movements during and prior to landing.

Effects of gait retraining using minimalist shoes on the medial gastrocnemius muscle-tendon unit behavior and dynamics during running.

The effects of a 12-week gait retraining program on the adaptation of the medial gastrocnemius (MG) and muscle-tendon unit (MTU) were investigated. 26 runners with a rearfoot strike pattern (RFS) were randomly assigned to one of two groups: gait retraining (GR) or control group (CON). MG ultrasound images, marker positions, and ground reaction forces (GRF) were collected twice during 9 km/h of treadmill running before and after the intervention. Ankle kinetics and the MG and MTU behavior and dynamics were quantified. Runners in the GR performed gradual 12-week gait retraining transitioning to a forefoot strike pattern. After 12-week, (1) ten participants in each group completed the training; eight participants in GR transitioned to non-RFS with reduced foot strike angles; (2) MG fascicle contraction length and velocity significantly decreased after the intervention for both groups, whereas MG forces increased after intervention for both groups; (3) significant increases in MTU stretching length for GR and peak MTU recoiling velocity for both groups were observed after the intervention, respectively; (4) no significant difference was found for all parameters of the series elastic element. Gait retraining might potentially influence the MG to operate at lower fascicle contraction lengths and velocities and produce greater peak forces. The gait retraining had no effect on SEE behavior and dynamics but did impact MTU, suggesting that the training was insufficient to induce mechanical loading changes on SEE behavior and dynamics.

Enhancing walking performance in patients with peripheral arterial disease: An intervention with ankle-foot orthosis

Lower extremity peripheral artery disease (PAD) is a cardiovascular condition manifesting from narrowed or blocked arteries supplying the legs. Gait is impaired in patients with PAD. Recent evidence suggests that walking with carbon fiber ankle foot orthoses (AFOs) can improve patient mobility and delay claudication time. This study aimed to employ advanced biomechanical gait analysis to evaluate the impact of AFO intervention on gait performance among patients with PAD. Patients with claudication had hip, knee, and ankle joint kinetics and kinematics assessed using a cross-over intervention design. Participants walked over the force platforms with and without AFOs while kinematic data was recorded with motion analysis cameras. Kinetics and kinematics were combined to quantify torques and powers during the stance period of the gait cycle. The AFOs effectively reduced the excessive ankle plantar flexion and knee extension angles, bringing the patients' joint motions closer to those observed in healthy individuals. After 3 months of the AFO intervention, the hip range of motion decreased, likely due to changes occurring within the ankle chain. With the assistance of the AFOs, the biological power generation required from the ankle and hip during the push-off phase of walking decreased. Wearing AFOs resulted in increased knee flexor torque during the loading response phase of the gait. Based on this study, AFOs may allow patients with PAD to maintain or improve gait performance. More investigation is needed to fully understand and improve the potential benefits of ankle assistive devices.

Quantifying walking speeds in relation to ankle biomechanics on a real-time interactive gait platform: a musculoskeletal modeling approach in healthy adults.

Background: Given the inherent variability in walking speeds encountered in day-to-day activities, understanding the corresponding alterations in ankle biomechanics would provide valuable clinical insights. Therefore, the objective of this study was to examine the influence of different walking speeds on biomechanical parameters, utilizing gait analysis and musculoskeletal modelling. Methods: Twenty healthy volunteers without any lower limb medical history were included in this study. Treadmill-assisted gait-analysis with walking speeds of 0.8m/s and 1.1m/s was performed using the Gait Real-time Analysis Interactive Lab (GRAIL®). Collected kinematic data and ground reaction forces were processed via the AnyBody® modeling system to determine ankle kinetics and muscle forces of the lower leg. Data were statistically analyzed using statistical parametric mapping to reveal both spatiotemporal and magnitude significant differences. Results: Significant differences were found for both magnitude and spatiotemporal curves between 0.8m/s and 1.1m/s for the ankle flexion (p < 0.001), subtalar force (p < 0.001), ankle joint reaction force and muscles forces of the M. gastrocnemius, M. soleus and M. peroneus longus ( = 0.05). No significant spatiotemporal differences were found between 0.8m/s and 1.1m/s for the M. tibialis anterior and posterior. Discussion: A significant impact on ankle joint kinematics and kinetics was observed when comparing walking speeds of 0.8m/s and 1.1m/s. The findings of this study underscore the influence of walking speed on the biomechanics of the ankle. Such insights may provide a biomechanical rationale for several therapeutic and preventative strategies for ankle conditions.

Mechanics of the foot and ankle joints during running using a multi-segment foot model compared with a single-segment model.

The primary purpose of this study was to compare the ankle joint mechanics, during the stance phase of running, computed with a multi-segment foot model (MULTI; three segments) with a traditional single segment foot model (SINGLE). Traditional ankle joint models define all bones between the ankle and metatarsophalangeal joints as a single rigid segment (SINGLE). However, this contrasts with the more complex structure and mobility of the human foot, recent studies of walking using more multiple-segment models of the human foot have highlighted the errors arising in ankle kinematics and kinetics by using an oversimplified model of the foot. This study sought to compare whether ankle joint kinematics and kinetics during running are similar when using a single segment foot model (SINGLE) and a multi-segment foot model (MULTI). Seven participants ran at 3.1 m/s while the positions of markers on the shank and foot were tracked and ground reaction forces were measured. Ankle joint kinematics, resultant joint moments, joint work, and instantaneous joint power were determined using both the SINGLE and MULTI models. Differences between the two models across the entire stance phase were tested using statistical parametric mapping. During the stance phase, MULTI produced ankle joint angles that were typically closer to neutral and angular velocities that were reduced compared with SINGLE. Instantaneous joint power (p<0.001) and joint work (p<0.001) during late stance were also reduced in MULTI compared with SINGLE demonstrating the importance of foot model topology in analyses of the ankle joint during running. This study has highlighted that considering the foot as a rigid segment from ankle to MTP joint produces poor estimates of the ankle joint kinematics and kinetics, which has important implications for understanding the role of the ankle joint in running.

Energy transfer in reactive movements as a function of individual stretch load

Background: By directly recording electromyographic activity profiles and muscle-tendon interaction, this study aimed to elucidate the mechanisms why well-trained track and field athletes (experts) are able to outperform untrained individuals without former systematic experience in reactive jump training (novices). In particular, reactive power output and the elastic recoil properties of the muscle-tendon unit (MTU) were of special interest. For this purpose, stiffness regulation on muscle and joint level, energy management in terms of storing or dissipating elastic energy were compared between experts and novices during various stretch loads.Methods: Experts were compared with novices during reactive drop jumps (DJs) from drop heights ranging between 25 and 61 cm. Delta kinetic energy (Ekin) was calculated as the difference between the Ekin at take-off and ground contact (GC) to determine energy management. By recording electromyography of the lower limb muscles, in vivo fascicle dynamics (gastrocnemius medialis) and by combining kinematics and kinetics in a 3D inverse dynamics approach to compute ankle and knee joint kinetics, this study aimed to compare reactive jump performance, the neuromuscular activity and muscle-tendon interaction between experts and novices among the tested stretch loads.Results: Experts demonstrated significantly higher power output during DJs. Among all drop heights experts realized higher delta Ekin compared to novices. Consequently, higher reactive jump performance shown for experts was characterized by shorter GC time (GCT), higher jump heights and higher neuromuscular activity before and during the GC phase compared to novices. Concomitantly, experts were able to realize highest leg stiffness and delta Ekin in the lowest stretch load; however, both groups compensated the highest stretch load by prolonged GCT and greater joint flexion. On muscle level, experts work quasi-isometrically in the highest stretch load, while in novices GM fascicles were forcefully stretched.Conclusion: Group-specific stiffness regulation and elastic recoil properties are primarily influenced by the neuromuscular system. Due to their higher neuromuscular activity prior and during the GC phase, experts demonstrate higher force generating capacity. A functionally stiffer myotendinous system through enhanced neuromuscular input enables the experts loading their elastic recoil system more efficiently, thus realizing higher reactive power output and allowing a higher amount of energy storage and return. This mechanism is regulated in a stretch load dependent manner.

Ankle Biomechanics During Multidirectional Landings in Athletes With Chronic Ankle Instability.

Assessing and understanding the control of the ankle during multidirectional jump landings in athletes with chronic ankle instability (CAI) would help health professionals develop interventions to reduce the risk of recurrent injuries. The aim of this study was to investigate the angle, angular velocity, and movements of the ankle joint, and the muscle activity of peroneus longus (PL), tibialis anterior (TA), and gastrocnemius (GAS) muscles during multidirectional landings in athletes with CAI. Nineteen athletes with CAI (≤25 Cumberland Ankle Instability Tool-Thai Score) participated. A Vicon Nexus motion analysis system synchronously collected data with an AMTI force plate and surface electromyography (EMG) to capture kinematics, kinetics, and muscle activity, respectively. Participants were asked to perform single-leg jump-landing tests in forward (0°), 30° diagonal, 60° diagonal, and lateral (90°) directions. Ankle joint kinematics, kinetics, and muscle activity of PL, TA, and GAS were analyzed. Repeated measure ANOVA (analysis of variance) and Friedman tests were used to analyze the main effects of the jump-landing direction. Athletes with CAI exhibited significant differences in ankle angles, angular velocities, ankle movements, and average muscle activity of GAS between directions. Greatest average EMG of GAS muscle was observed during landing in the lateral direction compared with the forward and 30° diagonal directions. Lateral and diagonal direction movements showed the greatest risks associated with recurrent ankle sprains. Impairments of neuromuscular control in both pre-landing and landing phases were observed in athletes with CAI when considered alongside previously published data. Laboratory-based observational study.

Mechanics of The Medial Gastrocnemius-Tendon Unit in Behaving more Efficiently in Habitual Non-Rearfoot Strikers than in Rearfoot Strikers during Running.

This study aims to quantify how habitual foot strike patterns would affect ankle kinetics and the behavior and mechanics of the medial gastrocnemius-tendon unit (MTU) during running. A total of 14 runners with non-rearfoot strike patterns (NRFS) and 15 runners with rearfoot strike patterns (RFS) ran on an instrumented treadmill at a speed of 9 km/h. An ultrasound system and a motion capture system were synchronously triggered to collect the ultrasound images of the medial gastrocnemius (MG) and marker positions along with ground reaction forces (GRF) during running. Ankle kinetics (moment and power) and MG/MTU behavior and mechanical properties (MG shortening length, velocity, force, power, MTU shortening/lengthening length, velocity, and power) were calculated. Independent t-tests were performed to compare the two groups of runners. Pearson correlation was conducted to detect the relationship between foot strike angle and the MTU behavior and mechanics. Compared with RFS runners, NRFS runners had 1) lower foot strike angles and greater peak ankle moments; 2) lower shortening/change length and contraction velocity and greater MG peak force; 3) greater MTU lengthening, MTU shortening length and MTU lengthening velocity and power; 4) the foot strike angle was positively related to the change of fascicle length, fascicle contraction length, and MTU shortening length during the stance phase. The foot strike angle was negatively related to the MG force and MTU lengthening power. The MG in NRFS runners appears to contract with greater force in relatively isometric behavior and at a slower shortening velocity. Moreover, the lengthening length, the lengthening velocity of MTU, and the MG force were greater in habitual NRFS runners, leading to a stronger stretch reflex response potentially.

Females with hip-related pain demonstrate reduced kinetics at the hip and ankle during terminal stance of gait

BackgroundIndividuals with hip-related pain (HRP) commonly report pain with walking and demonstrate altered movement patterns compared to healthy controls (HCs). Individuals with HRP may attempt to reduce pain during walking by decreasing kinetics and joint forces at the hip through increased use of the ankle during pushoff. Research questionDo individuals with HRP have increased kinetics at the ankle and decreased kinetics at the hip during pushoff in gait compared to HCs, and do kinetic patterns differ between males and females with HRP? MethodsThis retrospective observational study included 42 individuals with HRP and 20 HCs. Participants completed overground gait trials at their self-selected speed while kinematics and kinetics were recorded through a motion capture system and force plates. Peak internal hip and ankle moments and hip flexion and ankle plantarflexion angular impulse during terminal stance were used in general estimating equations for comparison of group by limb interactions for males and females separately, as well as a comparison of males and females within the HRP group. ResultsFemales with HRP demonstrated reduced hip flexion impulse on their involved limb (.070 Nm*s/kg*m) compared to female HCs (.083Nm*s/kg*m; p = .032), as well as reduced peak ankle plantarflexion moment (−.94Nm/kg*m) compared to their contralateral limb (−.99Nm/kg*m) and the involved limb of HRP males (−1.00Nm/kg*m) (p ≤ .007). There were no between-limb or between-group differences in hip or ankle peak moments or impulses in males. SignificanceFemales with HRP show decreased kinetics at both the hip and ankle; these patterns were not identified in males. Future investigations should examine whether increasing ankle kinetics during pushoff reduces pain at the hip, as this may be a valuable clinical treatment strategy.

Joint Coordination and Muscle-Tendon Interaction Differ Depending on The Level of Jumping Performance.

The countermovement jump is a popular measurement modality to evaluate muscle power in sports and exercise. Muscle power is essential to achieve a high jump, yet the well-coordinated movement of the body segments, which optimizes the stretch-shortening cycle (SSC) effects, is also required. Among the proposed explanations of SSC effects, this study investigated whether the ankle joint kinematics, kinetics, and muscle-tendon interaction depend on the level of jump skill and the jump task. Sixteen healthy males were grouped as a function of their jump height (High jumpers; greater than 50 cm, Low jumpers; less than 50 cm). They were instructed to jump with two intensities; light effort (20 % of their height) and maximal effort. Joint kinematics and kinetics of the lower limbs were analyzed using a 3-dimensional motion analysis system. The muscle-tendon interaction was investigated using B-mode real-time ultrasonography. As the jump intensity increased, all participants jumped with increased joint velocity and power. However, the high jumper shows less fascicle shortening velocity (-0.2 ± 0.1 m/s) than the low jumper group (-0.3 ± 0.1 m/s) and greater tendon velocity, which indicated the capability of elastic energy recoil. In addition, the delayed onset time of ankle extension in the high jumper implies better use of the catapult mechanism. The findings of this study showed that the muscle-tendon interaction differs depending on the jump skill level, suggesting a more efficient neuromuscular control in skilled jumpers.

Effects of shoelace tightness on lower limb biomechanics and subjective perception during lateral shuffle in basketball.

Purpose: Shoelace tightness is an important factor that may influence basketball players' performance and injury risk during shuttle slip movement. This study aimed to examine the effects of shoelace tightness on shoelace tension, lower limb kinematics and kinetics, and subjective perception in basketball players. Methods: Sixteen male college basketball players performed lateral shuffle movements with their dominant foot landing on a force plate under three shoelace tightness conditions (loose, comfortable and tight). A motion capture system and a force plate were used to measure lower limb kinematics and kinetics, respectively. A customized wireless shoelace tension system was used to measure shoelace tension at three locations on the dorsum of the foot. Visual analogue scales were used to assess perceived comfort, foot pressure and in-shoe displacement. Results: Shoelace tension increased with shoelace tightness (loose: 13.56 ± 6.21 N, comfortable: 16.14 ± 5.35 N, tight: 21.25 ± 6.19 N) and varied with shoelace position (front: 20.19 ± 5.99 N, middle: 13.71 ± 5.59 N, rear: 17.04 ± 6.95 N). Shoelace tightness also affected some of the ankle joint kinematics and kinetics as well as the subjective ratings of foot pressure and in-shoe displacement ( p < 0.05). The loose shoelace increased the ankle inversion angle, while the comfortable shoelace decreased the knee negative power. The tight shoelace increased the perceived foot pressure and reduced the inshoe movement ( p < 0.05). Conclusions: Shoelace tightness could significantly affect lower limb biomechanics and subjective perception during lateral shuffle in basketball. Basketball footwear designers should consider the incorporation of multiple shoelaces or zonal lacing systems to allow athletes to fine-tune the tension across different areas of the foot.

Muscle inertial contributions to ankle kinetics during the swing phase of running

Skeletal muscles have inertia that leads to inertial forces acting around joints. Although these inertial muscle forces contribute to joint kinetics, they are not typically accounted for in musculoskeletal models used for human movement biomechanics research. Ignoring inertial forces can lead to errors in joint kinetics, but how large these errors are in inverse dynamics calculations of common movements is yet unclear. We, therefore, examined the role of shank muscle inertia on ankle joint moments during the swing phase of running at different speeds. A custom musculoskeletal modelling and simulation platform was used to perform inverse dynamics with a model that either combined muscle mass in the total shank mass, or considered the gastrocnemius lateralis/medialis, soleus, and tibialis anterior muscles as separate masses from the shank. Ankle moments were considerably affected when muscles were modelled as separate masses, with a general shift towards reduced dorsiflexion and higher plantarflexion moments. Differences between both modelling conditions increased with running speed and ranged between 0.8 and 1.6 Nm (ankle moment profile root mean square error), 8–18 % (peak dorsiflexion moment difference) and 24–42 % (peak plantarflexion moment difference). Moreover, we observed a complex combination of inertial forces, especially those due to rotation and translation of the shank, in which the direction of inertial force changed during the swing phase. These results show that ignoring muscle inertia in musculoskeletal models can lead to under- or overestimations of structure-specific loads and thus erroneous study conclusions. Our results suggest that muscle inertial forces should be carefully considered when using musculoskeletal models.

Effects of Kettlebell Load on Joint Kinetics and Global Characteristics during Overhead Swings in Women.

This study sought to identify the changes in ankle, knee, and hip joint kinetics with increasing load while performing the kettlebell overhead swing (OHS). Women (n = 18, age: 29.4 ± 5.3 years, 69.7 ± 8.9 kg) with a minimum of 6 months of kettlebell swing training experience performed fifteen repetitions of the kettlebell OHS with three different kettlebell masses (8 kg, 12 kg, 16 kg) in a counterbalanced order. Ankle, knee, and hip joint kinematics were captured within a 12-camera infrared motion capture space, while standing atop two force plates collecting ground reaction force (GRF) data. Post hoc results of statistically significant joint by mass interactions (p &lt; 0.05) of the net joint moment impulse, work, and peak power revealed the hip demonstrating the greatest increase in response to load, followed by the ankle (p &lt; 0.05). The knee joint kinetics changed very little between the masses. Pairwise post hoc comparisons between the joints at each mass level support the kettlebell OHS as being a hip dominant exercise, with the knee making the second largest contribution, despite contributions not changing across kettlebell masses. Collectively, these results provide practitioners with objective evidence regarding the mechanical demands and effects of load changes on the kettlebell OHS.

Comparison of Joint-Level Kinetics During Single-Leg and Double-Leg Weightlifting Derivatives.

Hayashi, R, Yoshida, T, and Kariyama, Y. Comparison of joint-level kinetics during single- and double-leg weightlifting derivatives. J Strength Cond Res 37(5): 1017-1022, 2023-Humans have different 3-dimensional biomechanical characteristics of the lower extremities during locomotion with one and both legs. These biomechanical characteristics may also be observed in the weightlifting derivatives. This study aimed to compare the 3-dimensional joint kinetics of the lower extremities during the single-leg hang power clean (SHPC) and double-leg hang power clean (DHPC). Ten male track and field athletes performed the SHPC and DHPC using external loads of 30, 60, and 90% of one repetition maximum (1RM). The 1RMs in SHPC and DHPC were measured separately, and the external loads at 30, 60, and 90% of the 1RM used were determined based on the different 1RMs in SHPC and DHPC. We calculated the joint moment and joint power of the SHPC and DHPC using a motion capture system and force platforms. The hip abduction moment and power of the SHPC were significantly greater than those of the DHPC under all external loads ( p < 0.05). In addition, ankle joint moment at all external loads and joint power at 90% of 1RM was greater for SHPC than for DHPC ( p < 0.05). Furthermore, although hip (extension-flexion) and ankle joint kinetics in SHPC and DHPC showed similar load dependence, hip abduction axis kinetics was not load dependent. These results suggest that the hip (abduction-adduction) and ankle joint kinetics in SHPC are greater than in DHPC, but hip (abduction-abduction) kinetics in SHPC is not load independent.

Examining the intrinsic foot muscles’ capacity to modulate plantar flexor gearing and ankle joint contributions to propulsion in vertical jumping

BackgroundDuring human locomotion, a sufficiently stiff foot allows the ankle plantar flexors to generate large propulsive powers. Increasing foot stiffness (e.g., via a carbon plate) increases the ankle's external moment arm in relation to the internal moment arm (i.e., increasing gear ratio), reduces plantar flexor muscles’ shortening velocity, and enhances muscle force production. In contrast, when activation of the foot's intrinsic muscles is impaired, there is a reduction in foot and ankle work and metatarsophalangeal joint stiffness. We speculated that the reduced capacity to actively control metatarsophalangeal joint stiffness may impair the gearing function of the foot at the ankle. MethodsWe used a tibial nerve block to examine the direct effects of the intrinsic foot muscles on ankle joint kinetics, in vivo medial gastrocnemius’ musculotendinous dynamics, and ankle gear ratio on 14 participants during maximal vertical jumping. ResultsUnder the nerve block, the internal ankle plantar flexion moment decreased (p = 0.004) alongside a reduction in external moment arm length (p = 0.021) and ankle joint gear ratio (p = 0.049) when compared to the non-blocked condition. Although medial gastrocnemius muscle–tendon unit and fascicle velocity were not different between conditions, the Achilles tendon was shorter during propulsion in the nerve block condition (p < 0.001). ConclusionIn addition to their known role of regulating the energetic function of the foot, our data indicate that the intrinsic foot muscles also act to optimize ankle joint torque production and leverage during the propulsion phase of vertical jumping.

Evidence for symmetrically reduced foot mechanics and energetics in patients after trimalleolar fracture repair: A cross-sectional study

BackgroundTrimalleolar fractures osteosynthesis is associated with a suboptimal outcome. It is hypothesized that patients with trimalleolar fractures face different ankle joint kinetics at mid- and long-term causing compensations at the distal foot joints. Research questionDo patients with a history of a trimalleolar fracture demonstrate different foot joint mechanics and energetics (1) between their affected side and their matched controls? (2) between their unaffected side and their matched controls? (3) between their affected side and their unaffected side? MethodsFifteen patients who sustained a trimalleolar fracture and underwent osteosynthesis for both the lateral, medial and posterior malleolus were compared to a asymptomatic control group which was matched for sex, age and walking speed. Three-dimensional gait analysis was used to quantify kinetic parameters in the Ankle, Chopart, Lisfranc and first metatarsophalangeal joint through a multi-segment kinetic foot model. Statistical analysis was performed using a Univariate Analysis of Covariance and/or a paired t-test. ResultsThe peak internal ankle moment was significantly lower in patients when compared to the control group (p < 0.001). Mean peak power generation and total positive work were significantly lower for the Chopart joint when comparing the patients to the control group (p < 0.001). These results were observed for both the affected and unaffected side of the patients compared to the control group, showing symmetrical changes in the patient group. SignificanceDespite adequate radiographic quality of reduction and the fact that all patients were treated according to a fixed postoperative protocol, this study indicates that patients with a history of a trimalleolar fracture demonstrate reduced foot joint kinetics. It is hypothesized that these findings originate from extrinsic and intrinsic foot muscle strength, stiffness and pain. Future research is needed to validate this hypothesis.

Sagittal plane ankle kinetics are associated with dynamic hip range of motion and gait efficiency in women with hip osteoarthritis.

Loss of sagittal plane hip range of motion (ROM) is a commonly reported walking gait impairment in people with hip osteoarthritis (OA). The purpose of this study was to evaluate whether sagittal plane hip ROM reduction and the resulting altered sagittal plane ankle kinetics during gait influence the energy cost of walking in people with hip OA. We evaluated 24 women with unilateral hip OA (60 ± 9.1 years; 29.4 ± 6.1 kg/m2 ). Sagittal plane hip ROM and peak ankle dorsiflexion moment were assessed by instrumented gait analysis. We also used a portable metabolic system to measure the energy cost of walking. Pearson correlations and regression analyses were performed to test our hypotheses. We found that greater involved limb sagittal plane hip ROM was associated with a larger ankle peak dorsiflexion moment at push-off during gait (R = 0.50, p = 0.01). Greater involved limb peak ankle dorsiflexion moment at push-off was associated with a lower oxygen consumption during gait (R = -0.51, p = 0.01). Involved limb peak ankle dorsiflexion moment at push-off predicted 26% of the variance in O2 cost. Statement of Clinical Significance: Sagittal plane hip ROM was associated with peak ankle dorsiflexion moment at push-off during gait in women with hip OA. Moreover, peak ankle dorsiflexion moment at push-off was associated with the energy cost of walking. Therefore, modifying sagittal plane hip ROM and peak ankle dorsiflexion moment could be a possible rehabilitation strategy to improve gait efficiency in women with hip OA.

Immediate effects of transcutaneous electrical nerve stimulation on gait patterns in chronic stroke survivors: A single group, pretest-posttest clinical trial.

Transcutaneous electrical nerve stimulation (TENS) has been used to reduce muscle spasticity and improve locomotion in stroke survivors. We speculate that acute changes in gait performance after TENS mediate functional improvement in the long-term. However, no previous study has investigated the effect of TENS on ankle kinetics and kinematics during walking in stroke survivors. We aimed to investigate whether TENS applied over the paretic leg could rapidly improve the plantar flexion moment and ankle kinematics in chronic stroke survivors with lower limb paresis. Twenty chronic stroke survivors were recruited. They underwent 30min of TENS over the area innervated by the common peroneal nerve on the paretic leg. Three-dimensional (3D) motion capture was performed and ankle plantar flexor spasticity was assessed before and immediately after stimulation. Ankle kinematics and kinetic and spatiotemporal data were collected using 3D motion capture. Ankle plantar flexor spasticity was assessed using the Modified Tardieu Scale. A significant increase in the ankle plantar flexion moment of the paretic side during the pre-swing phase was observed immediately after stimulation (p=0.009, maximal mean difference=0.035, 95%CI=0.0125 to 0.0575). The step length of the paretic limb also increased significantly after stimulation (p=0.023, mean difference=-0.02, 95%CI=-0.04 to -0.004). TENS had no immediate effect on paretic ankle spasticity, as measured by the Modified Tardieu Scale, or on other temporo-spatial parameters. The findings support the use of TENS to improve the motor function and gait pattern in chronic stroke survivors. The study indicated that the application of TENS to the paretic leg before gait training might improve rehabilitation outcomes. Future studies investigating the effects of TENS on functional outcomes, the optimal stimulation duration, and assessing spasticity using more sensitive measures are warranted.

Ankle–foot orthosis with an oil damper versus nonarticulated ankle–foot orthosis in the gait of patients with subacute stroke: a randomized controlled trial

BackgroundGait improvement in patients with stroke has been examined in terms of use or non-use of an ankle–foot orthosis (AFO), but the effects of different kinds of AFOs remain unclear. In this study, the effect on gait of using an AFO with an oil damper (AFO-OD), which has plantarflexion stiffness without dorsiflexion resistance, was compared with a nonarticulated AFO, which has both dorsiflexion and plantarflexion stiffness, in a randomized controlled trial.MethodsForty-one patients (31 men, 10 women; mean age 58.4 ± 11.3 years) in the subacute phase of stroke were randomly allocated to two groups to undergo gait training for 1 h daily over 2 weeks by physiotherapists while wearing an AFO-OD or a nonarticulated AFO. A motion capture system was utilized to measure shod gait without orthosis at baseline and after training with the allocated AFO. Data analysis focused on the joint kinematics and kinetics, spatial and temporal parameters, ground reaction force, and shank-to-vertical angle. Unpaired t-test or Mann–Whitney U test was performed to clarify the difference in gait with an AFO between the two AFO groups after training, with a significance level of p = 0.05.ResultsThirty-six patients completed the study (17 in the AFO-OD group and 19 in the nonarticulated AFO group). The ankle joint was more dorsiflexed in single stance (p = 0.008, effect size r = 0.46) and peak ankle power absorption was larger in stance (p = 0.007, r = 0.55) in the AFO-OD group compared with the nonarticulated AFO group. Peak power absorption varied among patients in the AFO-OD group. Increased dorsiflexion angles were also found at initial contact (p = 0.008, r = 1.51), pre-swing (p = 0.045, r = 0.91), and the swing phase (p = 0.045, r = 0.91) in the AFO-OD group. There was no difference in peak plantarflexion moment, ankle power generation, spatial or temporal parameters, ground reaction force, or shank-to-vertical angle between the two groups.ConclusionsThe results of this study showed that an AFO with plantarflexion stiffness but without dorsiflexion resistance produced greater improvement in ankle joint kinematics and kinetics compared with the nonarticulated AFO, but the results of peak power absorption varied greatly among patients.Trial registration UMIN000028126, Registered 1 August 2017, https://upload.umin.ac.jp/cgi-bin/icdr/ctr_menu_form_reg.cgi?recptno=R000032197