Hip Kinetics Research Articles

REVIEW: PATELLOFEMORAL PAIN SYNDROME

Patellofemoral pain syndrome is a common musculoskeletal condition and a major cause for anterior knee pain. It has been associated with excessive compression between the patella and the lateral femoral condyle. It is one of those overuse disorder that can limit activity of daily living along with participation in sports. The prevalence is more on female than those of male with the ratio of 2:1 and it affect athletic female more solely due to greater internal rotation of femur during running which leads to greater hip adduction. The reason for patellofemoral pain syndrome have been multifactorial increased femoral internal rotation, decreased hip abduction and external rotation strength, decreased VMO function and lateral retinaculum tightness. These factor leads to increase in dynamic Q angle that directly increases patellofemoral contact pressure which map a way to patellofemoral pain syndrome. The literature will have an explanation about altered hip kinetics, kinematics and its association with patellofemoral pain syndrome along with rehab protocol for patients with the same condition.

Immediate Improvements in Patellofemoral Pain Are Associated With Sagittal Plane Movement Training to Improve Use of Gluteus Maximus Muscle During Single Limb Landing.

The authors sought to examine the immediate effects of movement training aimed at improving use of gluteus maximus (GMAX) in the sagittal plane on hip internal rotation and self-reported patellofemoral pain (PFP) during single-limb landing. Seventeen females with PFP participated. Lower extremity kinematics and kinetics, GMAX activation, and self-reported PFP were obtained before and after a single-session movement training program aimed at increasing the use of GMAX. Dependent variables of interest included self-reported PFP, average GMAX activation, average hip extensor moment, and peak hip internal rotation. Post-training changes were evaluated using paired t tests and Wilcoxon signed rank tests. Following movement training, self-reported PFP decreased significantly (mean [standard deviation]) (3.9 [1.1] vs 0.8 [1.3] on a 0-10 scale). Additionally, significant increases were observed for the average hip extensor moment (0.6 [0.3] vs 1.8 [0.4] Nm/kg) and average GMAX activation (41.0% [18.3] vs 51.6% [25.7] maximum voluntary isometric contraction), whereas peak hip internal rotation decreased significantly (8.5 degrees [5.8] vs 6.0 degrees [5.3]). Movement training aimed at improving the use of GMAX in the sagittal plane resulted in clinically relevant changes in self-reported pain, GMAX activation, and hip kinetics and kinematics. Improving the use of GMAX during movement merits consideration when designing rehabilitation programs for females with PFP. The current study highlights the clinical utility of movement training for persons with PFP and provides a biomechanical rationale for its use as a potential intervention in this population.

New Insights About the Sticking Region in Back Squats: An Analysis of Kinematics, Kinetics, and Myoelectric Activity.

The aim of this study was to investigate barbell, joint kinematics, joint kinetics of hip, knee, and ankle in tandem with myoelectric activity around the sticking region in three-repetition maximum (3-RM) back squats among recreationally trained lifters. Unlike previous literature, this study also investigated the event of first-peak deacceleration, which was expected to be the event with the lowest force output. Twenty-five recreationally trained lifters (body mass: 70.8 ± 10.5, age: 24.6 ± 3.4, height: 172 ± 8.5) were tested in 3-RM back squats. A repeated one-way analysis of variance showed that ground reaction force output decreased at first peak deacceleration compared with the other events. Moreover, torso forward lean, hip moment arm, and hip contribution to total moment increased, whereas the knee moment arms and moment contribution to total moment decreased in the sticking region. Also, stable moment arms and moment contributions to total moment were observed for the ankle in the sticking region. Furthermore, the knee extensors together with the soleus muscle decreased myoelectric activity in the post-sticking region, while the gluteus maximus and biceps femoris increased myoelectric activity in the post-sticking region. Our findings suggest that the large hip moment arms and hip contributions to total moment together with a lower myoelectric activity for the hip extensors contribute to a poor biomechanical region for force output and, thereby, to the sticking region among recreationally trained lifters in 3-RM back squats.

Rounding the base: A lower extremity biomechanical analysis in softball players

Contacting the base is a common injury mechanism for base runners in softball, with ankle sprains being the most common type of injury, but it is not known how the base affects lower extremity mechanics. The purpose of this study was to analyze lower extremity biomechanics while rounding a base. Sixteen recreationally active females with previous softball experience completed two base rounding conditions. A base was securely placed on the force place for the with base (WB) condition, and an outline of the base was taped on the force plate for the no base (NB) condition. Three-dimensional right-leg hip, knee, and ankle kinematics and kinetics were measured during the stance phase of the base rounding and analyzed using statistical parametric mapping (SPM). The WB condition resulted in decreased hip abduction ( p = 0.034), increased dorsiflexion ( p = 0.012), and decreased inversion ( p < 0.001) angles. Increased hip extension ( p < 0.001) and hip abduction ( p = 0.016) moments were exhibited during the WB condition. Decreased hip abduction ( p = 0.026), ankle plantarflexor ( p < 0.001), and ankle eversion ( p < 0.001) moments were also exhibited in the WB condition. The base acts as a lateral banking surface, reducing variables associated with ankle sprains, and likely assists in propelling base runners to the next base without injury.

Hip biomechanical alterations during walking in chronic ankle instability patients: a cross-correlation analysis

ABSTRACT Chronic ankle instability (CAI) patients often present with centrally-mediated neuromuscular adaptations. Gluteal thickness measures derived from ultrasound imaging (USI) have been correlated to hip biomechanical measures during walking among healthy individuals, however these relationships remain unexplored among CAI patients. The purpose of this study was to compare USI-derived gluteus maximus and medius thickness measures to tri-planar hip kinematics, kinetics, and gluteus medius surface electromyography (sEMG) amplitude during walking among CAI patients. Fifteen females with CAI walked on a treadmill while USI, hip tri-planar kinematics, kinetics, and sEMG were synchronously recorded. Cross-correlation analyses were conducted at 1% intervals (11-ms) from −20% to 20% in the gait cycle. Gluteus medius thickness measures were associated with frontal plane kinematics at a 99-ms lag (cross-correlation coefficient [CCF]: −0.61), transverse plane kinematics at a 66-ms lag (CCF: −0.69), and with hip kinetics at 110-ms lags (CCF: 0.51–0.55). Gluteus medius thickness measures followed sEMG amplitudes by 143-ms (CCF: 0.22). Gluteus maximus thickness was associated with sagittal kinematics at a 220-ms lag (CCF: −0.70), and thickness changes preceded sagittal kinetics at 200-ms (0.87). Compared to reference healthy data, the CAI group presented with differing lag times between USI-derived measures and hip biomechanics, suggesting neuromechanical alterations during walking.

Habitual endurance running does not mitigate age-related differences in gait kinetics.

Older adults often walk with smaller ankle joint kinetics and larger hip joint kinetics compared to young adults. These age-related differences have been attributed, in part, to weaker plantarflexor muscles. While it is thought that regular physical activity helps to maintain muscle strength and mobility in older adults, physical activity levels on average decline with age. Therefore, understanding the effect of physical activity level on gait kinetics is an important objective for the management of mobility impairment in older adults. The purpose of this study was determine the effect of habitual endurance running on lower-extremity joint kinetics. 12 male older long-term runners (67±5yrs., 1.79±0.07m, 77.3±13.7kg) and 12 male older non-runners (70±3yrs., 1.78±0.06m, 79.68±10.6kg), performed overground walking trials at 1.3m/s while kinematic and kinetic data were collected. Participants also performed maximal voluntary contractions at the hip, knee, and ankle joints on an isokinetic dynamometer. Older runners displayed similar ankle plantarflexor strength, similar hip extensor strength, and greater knee extensor strength compared to older non-runners, and walked with similar ankle joint kinetics (p>0.05), and larger hip joint kinetics compared to older non-runners (p<0.05). Thus, physical activity, in the form of running at least 20miles/wk. and training for at least one race per year, did not mitigate the characteristic age-related differences in gait kinetics. Our findings may indicate that age-related differences in lower-extremity gait kinetics are a normal consequence of natural aging.

Do Novice Runners Show Greater Changes in Biomechanical Parameters?

Purpose Examining and understanding the biomechanics of novice runners and experienced runners can further improve our knowledge within the field of running mechanics and running injuries. The purpose of this study was to classify the differences in lower limb biomechanics during a 3.3 m/s running task among both experienced runners and novice runners. Method Twenty-four participants (12 experienced runners and 12 novice runners) ran at 3.3 m/s across a force plate; kinematics and kinetics data were collected by the Vicon motion system and Kistler force plate. Group comparisons were made using an independent samples t-test to identify differences in the impact peak, loading rate, contact time, ankle, knee, and hip joint kinematics and kinetics during the stance phase. Results No significant differences were observed between novice and experienced runners for both ankle and knee joint kinetics except that the ankle joint plantar flexion torque was significantly greater in the novice runners. However, the plantar flexion, dorsiflexion, range of motion (ROM), plantar flexion torque, and max angular velocity of ankle joint significantly increased in novice runners than inexperienced runners. Additionally, the flexion angle and range of motion of the hip joint were observed to be larger in the novice runners. Moreover, the maximum extension torque and the maximum extension power in the hip joint were significantly increased in the experienced runners. There were no significant differences in the first peak, contact time, and average vertical loading rate. Novice runners showed a larger vertical instantaneous loading rate than experienced runners. Conclusion These preliminary findings indicate that novice runners are prone to running injuries in comparison to experienced runners. Novice runners showed larger kinematics and kinetic parameters in the joint of the ankle and hip. Novice runners should enhance muscle strength in the hip and choose scientific training methods.

Type of unanticipated stimulus affects lower extremity kinematics and kinetics during sidestepping

ABSTRACT Including an unanticipated stimulus has significant impacts on lower extremity biomechanics during dynamic movements. It is unknown how a live, human defender affects lower extremity biomechanics. The purpose of this study was thus to determine the effects of two types of unanticipated stimuli (visual stimulus; defensive opponent) on lower extremity kinematics and kinetics in males and females during 45° sidestepping trials. Eight males and eight females completed two unanticipated stimuli sidestepping conditions. Numeric visual analog scales for reaction difficulty and movement realism were collected and analysed using a 2 × 2 mixed-model ANOVA. Three-dimensional hip, knee, and ankle kinematics and kinetics were measured during the stance phase of the sidestep and analysed using statistical parametric mapping. Participants reported greater difficulty and less realistic movements with the visual stimulus. Unanticipated stimulus main effects were observed for knee abduction angle, and hip extension and adduction, and knee extension and adduction moments. Sex main effects were observed for hip flexion, hip abduction, and ankle dorsiflexion angles, as well as hip abduction, ankle plantarflexion and ankle eversion moments and vertical ground reaction forces. Participants responded differently to two unanticipated stimuli. Careful consideration should be used when determining the type of unanticipated stimulus used.

No difference in gait pattern between a short collum femoris-preserving and a conventional stem: 44 randomised total hip arthroplasty patients stem evaluated after 2 years.

The uncemented collum femoris-preserving (CFP) stem offers preservation of the femoral neck and a more conservative soft tissue resection, which may facilitate a more normal walking pattern. We used gait analysis to evaluate if patients operated with a CFP stem showed more favourable hip kinematics and kinetics when compared with a group of patients operated with a conventional uncemented stem. 44 patients randomised to receive either a CFP or a Corail stem were studied and were operated using a direct lateral incision. Gait analysis was performed 2 years after the operation with a 12-camera motion capture system and 2 force plates. Hip kinematics and kinetics were analysed and 66 subjects served as controls. None of the variables: speed, stride, cadence and stance showed any statistical significant difference between the 2 study groups. Neither did the hip kinematics and kinetics. Compared to controls, patients operated with the CFP stem showed an increased stance (62.5% vs. 61.1%, p < 0.006) and decreased hip abduction (-2.1° vs. -6.5°). Patients operated with the Corail stem showed decreased speed (1.18 vs. 1.23 m/second), and stride length (1.26 vs. 1.33 m), decreased hip extension (-7.5° vs. -12.8°) and range of hip flexion/extension (38° vs. 40.9°), as well as their hip adduction that was increased (6.3° vs. 4°), whereas their hip abduction was reduced (-2.8° vs. -6.5°), (p < 0.004) compared to the controls. Use of a CFP stem did not significantly influence any of the gait parameters studied when compared to a standard stem, but still both stems studied were associated with gait deviations when compared to controls. Whether these differences could be attributed to the stem used, the underlying hip disease, or both is still unknown.

Kinematics and kinetics of lower-extremity joints in parachuting landing with backpack and knee brace

Injuries on lower-extremity joints were caused by high impact force in parachuting landing. Knee brace was used to protect knee by restraining motion of knee. Backpack was necessary in parachuting landing and would increase lower-extremity joints injuries. This study aimed to analyze kinematics and kinetics of hip, knee and ankle for investigating multi-joint protection of knee brace for those joints in parachuting landing with backpack. Seven participants landed from 120 cm height. Kinematics and kinetics of hip, knee and ankle were analyzed. It was found that without backpack knee brace decreased angular displacements of hip (12.0%), knee (10.3%) and ankle (18.6%) on sagittal plane and angular velocities of hip (11.9%), knee (6.6%) and ankle (20.9%) on sagittal plane. With backpack, knee brace decreased angular displacement (5.5%) and angular velocity of knee (6.2%) on sagittal plane, but did not significantly influence those of hip and ankle on sagittal plane. Ground reaction force, joint moments and joint energy absorptions were not significantly influenced with knee brace. In conclusion, in parachuting landing without backpack, knee brace could provide multi-joint protection for hip, knee and ankle. In parachuting landing with backpack, knee brace could still protect knee, but could not protect hip and ankle.

Hip kinetics, kinematics, and motor control differences between normal and leg length discrepancy (LLD) children during gait: Simulation and experimental

Sustainability is a recent concern integrating environmental, economic, and societal worries.First and foremost, sustainable plastics must obey general sustainability criteria and specific criteria linked to their particular features. The goal of this chapter is to help define sustainability, examine the main drivers of change and propose some hypotheses of changes in the overall environment. The booming consumption of goods due to population growth and improvement in standards of living increase problems of sustainability and lead to a new approach of material selection taking into account more sustainable materials and better management of waste generation, reuse, and recycling.Environment damages and risks induced by climate change, greenhouse gases (GHGs), sea level rise, and biological concerns are examined as well as benefits coming from natural and artificial GHG sinks.An overview of specific plastics’ features, demand, diversity, potential pollutants, specific environmental issues, visual pollution and marine litter, and high lifetimes of waste alert the reader and help to get a more accurate understanding of the extent of the problem.Lastly, this chapter examines two aspects of sustainability that are of prime importance for the plastics industry: (1) the preferential use of renewable energy (demand forecast, potential energy sources, survival of traditional sources) and (2) the water footprint.

Comparison the effect of kinetic parameters of innovative storing-restoring hybrid passive (comfort gait) ankle-foot orthosis (AFO) with posterior leaf spring AFO in drop-foot patients: a prospective cohort study

Background: Drop-foot syndrome is a disorder in which the dorsiflexor muscles are weakened or completely paralyzed, leading to foot slapping after the initial contact and foot-dragging during the swing phase. Passive and hybrid passive ankle-foot orthoses (AFOs) are often prescribed as an intervention for this disorder; however, the effects of these AFOs on kinetic parameters during the gait of drop-foot patients seem unclear. This study aimed to compare the affected lower limb joints of ankle, knee, and hip kinetics parameters (moments and powers) during walking in drop-foot patients using an innovative AFO storing-restoring hybrid passive AFO, named “Comfort Gait” and posterior leaf spring (PLS) AFO. Methods: Ten drop-foot patients were recruited in the current study to walk at a comfortable self-selected speed while wearing two different AFO selections. Kinetic parameters with a motion capture system were obtained for these patients. Results: The results of this study revealed a significant increase in the peak values of kinetic parameters of the lower limb of the affected side (ankle, knee, and hip moments and powers) with the innovative designed AFO when compared to PLS AFO (P&lt;0.05). Conclusions: The significant increase of kinetic parameters in drop foot with use of the Comfort Gait as compared to the PLS AFO might suggest the effectiveness of this innovative AFO in improving the gait of foot drop patients more than the use of PLS AFO. Level of Evidence: Level II

Lower-limb joint kinetics in jump rope skills performed by competitive athletes

ABSTRACT The purpose of this study was to characterise lower-limb joint kinetics during consecutive double unders and speed step sprints performed by competitive jump rope athletes, and to compare these measurements to running. Sixteen adolescent competitive jump rope athletes performed consecutive double under, speed step, and running trials while motion capture and ground reaction force data were collected. Lower-limb joint moments, power, and work were calculated using an inverse dynamics approach and discrete measurements were compared between skills. Peak ground reaction forces were similar between movements; however, knee and hip joint kinetics were distributed differently between double unders and speed step. In general, double unders were characterised by an increased reliance on knee joint kinetics, while speed step was characterised by an increased reliance on hip joint kinetics. Peak ankle moments were 9–20% greater in speed step when compared to double unders and running (p ≤ 0.050), and peak negative ankle power was 39–114% greater in double unders and speed step when compared to running (p ≤ 0.002). These findings may have important implications for injury risk and load management in jump rope athletes or other individuals that incorporate jump rope into their training programs.

Breast Support Alters Knee Joint Biomechanics During A Landing Task.

Females have a greater rate of traumatic knee injuries than male athletes. Trunk position has been shown to affect knee joint biomechanics during a landing task. Given the position of breast tissue, insufficiently supported breasts may also alter knee joint biomechanics. However, no previous research has investigated the effect of breast tissue or support on knee joint biomechanics during landing. PURPOSE: to determine the effect of breast support on knee and hip joint kinetics during a landing task. METHODS: Fifteen female athletes performed five step-off landings from a height of 40 cm in each of three bra support conditions: control (CON), low support (LOW) and high support (HIGH). 3D kinematics and ground reaction forces (GRFs) were simultaneously recorded using a 9-camera motion capture system (240 Hz,) and pair of force platforms (1200 Hz,)..) was used to calculate knee and hip joint angles and moments. Custom software (was used to determine peak joint angles and moments. Repeated measures ANOVAs with Tukey’s post-hoc analyses were used to compare mean knee and hip joint kinetics. RESULTS: No differences in peak knee abduction moments were observed, though peak knee external rotation moments were smaller in the LOW compared to CON (p = 0.007) and HIGH conditions (p = 0.013). No differences were observed between CON and HIGH (p = 0.423). No differences were observed in peak hip abduction moment or peak hip external rotation moment. CONCLUSIONS: These findings indicate that knee joint biomechanics during a landing task are affected by breast support. The current study did not address the role of trunk orientation or differences in breast size amongst participants. Future research should address the role of breast motion on trunk kinematics and kinetics.Table 1: Mean knee and hip joint moments in the CON, LOW and HIGH support conditions.

The Effect Of Verbal Cues On Lower Extremity Kinetics During Running

Previous research indicates that verbal cues such as “push with your feet” can alter ankle and hip kinetics during walking. Clinicians often use cues such as “push with your hips” when working with runners, but the effect of such verbal cues on lower extremity kinetics during running remains poorly understood. PURPOSE: The purpose of this study was to determine the effect of verbal cues emphasizing use of hips and glutes or use of toes and ankles on lower extremity running kinetics. METHODS: Ten healthy subjects (age 23±1 years, mass 67±16 kg, height 168±11 cm) participated. Subjects performed 3 running trials, at a self-selected pace, on an instrumented treadmill while collecting kinematics and kinetics. First, a baseline running gait was established, then each subject was given the instruction to “push yourself forward with your hips and glutes” or “push yourself forward with your toes and ankles” in a randomized order. After 1 minute to adapt to each condition, 30 seconds of data were recorded. Variables of interest included peak sagittal hip, knee, and ankle moments and positive, negative, and total sagittal work at the hip, knee, and ankle. One-way repeated measures ANOVAs were used to assess kinetic changes across conditions. RESULTS: There was a significant main effect of running cue with respect to negative and total work at the ankle (p=0.031 and p=0.002). Post-hoc analyses indicated that ankle negative work was greater when running with the ankle cue compared to baseline running (-0.44±0.17 J/kg vs -0.38±0.14 J/kg; p=0.031) and ankle total work was greater when running with the ankle cue compared with baseline and hip cue running (p=0.019 - 0.008). There were no significant differences in any of the other lower extremity sagittal moments or work across tasks (p>0.05). CONCLUSIONS: Subjects demonstrated increased negative and total work at the ankle in response to the ankle running cue. There was no change in positive work, which was anticipated with a cue emphasizing forward propulsion. Running kinetics remained largely unchanged in response to either running cue, possibly due to the quality of the cue (i.e. internal rather than external focus). These data suggest telling clients to “use your hip more to run” may not be an effective method to change running mechanics.

Biomechanics of graded running: Part II-Joint kinematics and kinetics.

Compared to level running (LR), different strategies might be implemented by runners to cope with specific challenges of graded running at different speeds. The changes in joint kinetics and kinematics associated with graded running have been investigated, but their interactions with speed are unknown. Nineteen participants ran on an instrumented treadmill at five grades (0°, ±5° and±10°) and three speeds (2.50, 3.33 and 4.17m/s), while 3D motion and forces were recorded. Three speed×five-grade repeated-measures ANOVA was used to analyze kinetic and kinematic variables. A speed×grade interaction was observed for hip range of motion (ROM). Downhill running (DR) at fastest speed did not reduce ROM at the hip, compared to LR. Compared to LR, it was observed that the hip joint was responsible for a greater contribution of energy generation while running at the fastest speed at +10°. Speed×grade interactions were also observed for the energy absorption, peak moment, and peak power at the knee. Contrary to LR, running faster during UR did not require higher peak power at the knee. Finally, DR at the fastest speed did not increase peak negative power at the knee compared to LR. This study demonstrates that ankle, knee, and hip joint kinetics depend on speed and grade of running, while the effect of grade on joint kinematics was not substantially modulated by speed.

Soft tissue artifact causes underestimation of hip joint kinematics and kinetics in a rigid-body musculoskeletal model

Rigid body musculoskeletal models have been applied to study kinematics, moments, muscle forces, and joint reaction forces in the hip. Most often, models are driven with segment motions calculated through optical tracking of markers adhered to the skin. One limitation of optical tracking is soft tissue artifact (STA), which occurs due to motion of the skin surface relative to the underlying skeleton. The purpose of this study was to quantify differences in musculoskeletal model outputs when tracking body segment positions with skin markers as compared to bony landmarks measured by direct imaging of bone motion with dual fluoroscopy (DF). Eleven asymptomatic participants with normally developed hip anatomy were imaged with DF during level treadmill walking at a self-selected speed. Hip joint kinematics and kinetics were generated using inverse kinematics, inverse dynamics, static optimization and joint reaction force analysis. The effect of STA was assessed by comparing the difference in estimates from simulations based on skin marker positions (SM) versus virtual markers on bony landmarks from DF. While patterns were similar, STA caused underestimation of kinematics, range of motion (ROM), moments, and reaction forces at the hip, including flexion-extension ROM, maximum internal rotation joint moment and peak joint reaction force magnitude. Still, kinetic differences were relatively small, and thus they may not be relevant nor clinically meaningful.

Can kinematic and kinetic differences between planned and unplanned volleyball block jump-landings be associated with injury risk factors?

IntroductionInjury prevention programs for athletes are still limited by a lack of understanding of specific risk factors that can influence injuries within different sports. The majority of studies on volleyball have not considered the movement patterns when moving in different directions or in planned and unplanned block jump-landings. MethodsThis study investigated all planes mechanics between the lead and trail limb when moving in dominant and non-dominant directions, for both planned and unplanned jump-landings in thirteen semi-professional female volleyball players. Ankle, knee and hip joint kinematics, kinetics and joint stiffness were recorded. ResultsOur results showed statistically significant differences between the lead limb and the trail limb in the hip flexion angles, moments and velocity; in the knee flexion angles, moments, stiffness, power and energy absorption and in the ankle dorsiflexion, power and energy absorption, showing a tendency where the lead limb has a higher injury risk than the trail limb. When considering planned versus unplanned situations, there were statistically significant differences in knee flexion angles, moments, power and energy absorption; and hip contact angle, flexion angular velocity and energy absorption, with musculoskeletal adaptations in the planned situations. DiscussionIt appears that the role of the limb, either lead or trail, is more important than the limb dominance when performing directional jump-landings, with the lead limb having a higher implication on possible overuse injuries than the trail limb. Furthermore, planned movements showed a difference in strategy indicating greater implications to possible overuse injuries than in the unplanned situations which may be associated with more conscious thought about the movements. ConclusionCoaches should consider unilateral coordination training in both landing directions for the lead and trail limb, and should adapt training to replicate the competition environment, using unplanned situations to minimize asymmetries to might reduce injury risks.

Effects of Self-Selected Step Length and Trunk Position on Joint Kinetics in Highly Physically Fit Older Adults.

The causes of age-related differences in lower-extremity joint moments and powers are unknown. The purpose of this study was to determine the effects of highly physically active older adults walking with (1)a step length similar to young adults and (2)an upright trunk posture, on hip and ankle joint kinetics. The authors hypothesized that, compared with their self-selected walking mechanics, older adults would exhibit decreased hip kinetics and increased ankle kinetics when prescribed a young adult step length, and would exhibit decreased hip extension moments when maintaining an upright trunk posture during walking. A total of 12 active older adults (67 [5]y) and 13 active young adults (21 [3]y) walked at 1.3m/s. The older adults also walked at 1.3 m/s with step lengths prescribed from height-matched young adults and, in a separate condition, walked with an upright trunk. The older adults did not display larger ankle kinetics or smaller hip kinetics in either condition compared to walking with a self-selected step length. These findings indicate that step length and trunk position do not primarily contribute to age-related differences in kinetics in highly active older adults and should serve as a starting point for investigating alternative explanations.

Studying the Effects of Using Two Types of Afos on the Hip Joint Kinematics and Kinetics during Walking in the Sagittal Plane for a Patient with Severe DDH; Part 1

Developmental Dysplasia of the hip DDH is considered as one of the most common Orthopedic Disorders, referring to a range of conditions from mild to severe dislocation of the hip joint. However, there are unclear gait alterations in individuals with DDH such as the investigation of the Ankle and Knee devices AFOs and their effect on the kinematics and kinetics of the joints during walking and running. This paper aimed to study and evaluate the kinematics and kinetics of the ankle and knee joints during walking in the sagittal plane for a patient age 26 with severe dysplasia of the left hip who is experiencing using two different types of ankle-foot Orthosis (Custom-made, and Leaf-AFO). The data were collected using ten cameras and one force plate. We used an inverse dynamic approach to calculate sagittal joint angles, moments and power. The results pointed out that the planter flexion angle reached the maximum during the time between the Toes-off the ground phase and the initial swing phase significantly by mean difference (21.1, 14 deg). Moreover, the results indicated that the fabricated orthosis has decreased both the right and left extensor moments significantly during the load-bearing phase in comparison to Barefoot by mean difference (0.29, and 0.43 Nm/kg) respectively for both limbs. The paper concluded that the kinematics and kinetics of the ankle joint improved by the Custom made-Orthosis more than that of the Leaf AFO-Spring Orthoses. Finally, it concluded that both AFOs did not change much the kinematics of the knee joint; however, there were some improvements in the moments and power generated.