Soft soled footwear has limited impact on toddler gait

The development of walking in young toddlers is an important motor milestone. Walking patterns can differ widely amongst toddlers, and are characterised by unique biomechanical strategies. This makes comparisons between newly walking toddler’s and older children’s walking difficult. Little is currently understood regarding the effects of footwear on the gait in newly walking toddlers. A quasi-experimental pre-post study design was used to assess whether spatiotemporal parameters of gait, and in-shoe foot and lower limb kinematics, differed when walking barefoot and in soft-soled footwear in newly walking toddlers. There were 18 toddlers recruited, with 14 undergoing testing. The GAITRite system collected spatial and temporal data. The Vicon camera system collected kinematic data. The testing conditions included barefoot and footwear. Footwear tested was a commercially available soft soled shoe (Bobux XPLORER). Data was extracted directly from the GAITRite system and analysed. Walking in footwear did not change spatial or temporal data, however there were small but significant decreases in hip adduction/abduction range of motion (mean difference (MD) = 1.79°, 95% CI = -3.51 to -0.07, p = 0.04), knee flexion (MD = -7.63°, 95% CI = 2.70 to 12.55, p = 0.01), and knee flexion/extension range of movement (MD = 6.25°, 95% CI = -10.49 to -2.01, p = 0.01), and an increase in subtalar joint eversion (MD = 2.85°, 95% CI = 5.29 to -0.41, p = 0.03). Effect sizes were small for hip and ankle range, peak knee extension, and subtalar joint ranges (d<0.49), medium for knee flexion/extension range (d = 0.75) and large for peak knee flexion (d = 0.87). The magnitude of kinematic changes with soft-soled footwear were small thus the clinical importance of these findings is uncertain. Future longitudinal studies are needed to develop recommendations regarding footwear for newly walking toddlers.

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Military Protein Intake Related to Strength and Fat Mass Independent of Energy Intake

Military Medicine ◽

10.1093/milmed/usaa151 ◽

2020 ◽

Vol 185 (9-10) ◽

pp. e1671-e1678

Author(s):

Jeremy A Ross ◽

D Travis Thomas ◽

Joshua D Winters ◽

Scott D Royer ◽

Christopher J Halagarda ◽

...

Keyword(s):

Energy Intake ◽

Body Mass ◽

Knee Flexion ◽

Protein Intake ◽

Performance Metrics ◽

Knee Extension ◽

Special Operations ◽

Knee Extension Strength ◽

Peak Knee ◽

Flexion Strength

ABSTRACT Introduction Kinetic military units operate in austere training environments and deprivation not commonly experienced by competitive athletes. Nutritional strategies to protect against decrements in performance and potential injury risk may differ for these two groups. A cross sectional analysis was conducted to determine energy and macronutrient characteristics associated with performance metrics. Materials and Methods 78 male subjects (age: 28.4 ± 6.0 years, height: 178.3 ± 6.7 cm, mass: 84.3 ± 9.4 kg, 8.5 ± 5.8 years of service) assigned to Marine Corps Forces Special Operations Command completed a 1-day performance assessment. Body mass, lean body mass, fat mass (FM), aerobic capacity (VO2max), lactate inflection point (LT), anaerobic power, anaerobic capacity, knee flexion strength, knee extension strength, peak knee flexion strength, and peak knee extension strength outcome values were recorded. Dietary intake was collected using automated self-administered 24-hour dietary recall (ASA24). Performance assessment scores were compared with macronutrient intake and controlled for energy intake using analysis of covariance. Results Differences in knee flexion strength, knee extension strength, peak knee flexion strength, and peak knee extension strength were significant across low (LPRO), medium (MPRO), and high (HPRO) protein intake groups (p < 0.05) with LPRO performance metrics significantly lower than both MPRO and HPRO and MPRO significantly lower than HPRO. FM was significantly higher in LPRO than MPRO or HPRO (p < 0.05). Low carbohydrate intake (LCHO) was associated with greater body mass and FM compared with high (HCHO) (p < 0.05). There was no association between fat intake and any variable. Conclusions Increases in protein intake may have beneficial performance effects independent of total energy intake, while moderate increases in carbohydrate intake may not be sufficient to enhance physical performance in a special operations population.

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Relationship between Hip and Knee Strength and Knee Valgus during a Single Leg Squat

Journal of Applied Biomechanics ◽

10.1123/jab.22.1.41 ◽

2006 ◽

Vol 22 (1) ◽

pp. 41-50 ◽

Cited By ~ 174

Author(s):

Tina L. Claiborne ◽

Charles W. Armstrong ◽

Varsha Gandhi ◽

Danny M. Pincivero

Keyword(s):

Knee Flexion ◽

Frontal Plane ◽

Peak Torque ◽

Knee Extension ◽

Valgus Knee ◽

Knee Motion ◽

Knee Strength ◽

Flexion Extension ◽

Hip Abduction ◽

Single Leg Squat

The purpose of this study was to determine the relationship between hip and knee strength, and valgus knee motion during a single leg squat. Thirty healthy adults (15 men, 15 women) stood on their preferred foot, squatted to approximately 60 deg of knee flexion, and returned to the standing position. Frontal plane knee motion was evaluated using 3-D motion analysis. During Session 2, isokinetic (60 deg/sec) concentric and eccentric hip (abduction/adduction, flexion/extension, and internal/external rotation) and knee (flexion/extension) strength was evaluated. The results demonstrated that hip abduction (r2= 0.13), knee flexion (r2= 0.18), and knee extension (r2= 0.14) peak torque were significant predictors of frontal plane knee motion. Significant negative correlations showed that individuals with greater hip abduction (r= –0.37), knee flexion (r= –0.43), and knee extension (r= –0.37) peak torque exhibited less motion toward the valgus direction. Men exhibited significantly greater absolute peak torque for all motions, excluding eccentric internal rotation. When normalized to body mass, men demonstrated significantly greater strength than women for concentric hip adduction and flexion, knee flexion and extension, and eccentric hip extension. The major findings demonstrate a significant role of hip muscle strength in the control of frontal plane knee motion.

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Effects of Prophylactic Knee Bracing on Lower Limb Kinematics, Kinetics, and Energetics During Double-Leg Drop Landing at 2 Heights

The American Journal of Sports Medicine ◽

10.1177/0363546516637178 ◽

2016 ◽

Vol 44 (7) ◽

pp. 1753-1761 ◽

Cited By ~ 6

Author(s):

Katie A. Ewing ◽

Rezaul K. Begg ◽

Mary P. Galea ◽

Peter V.S. Lee

Keyword(s):

Knee Flexion ◽

Knee Extension ◽

Flexion Angle ◽

Initial Contact ◽

Knee Brace ◽

Acl Injuries ◽

Negative Power ◽

Peak Knee ◽

Knee Braces ◽

Biomechanical Factors

Background: Anterior cruciate ligament (ACL) injuries commonly occur during landing maneuvers. Prophylactic knee braces were introduced to reduce the risk of ACL injuries, but their effectiveness is debated. Hypotheses: We hypothesized that bracing would improve biomechanical factors previously related to the risk of ACL injuries, such as increased hip and knee flexion angles at initial contact and at peak vertical ground-reaction force (GRF), increased ankle plantar flexion angles at initial contact, decreased peak GRFs, and decreased peak knee extension moment. We also hypothesized that bracing would increase the negative power and work of the hip joint and would decrease the negative power and work of the knee and ankle joints. Study Design: Controlled laboratory study. Methods: Three-dimensional motion and force plate data were collected from 8 female and 7 male recreational athletes performing double-leg drop landings from 0.30 m and 0.60 m with and without a prophylactic knee brace. GRFs, joint angles, moments, power, and work were calculated for each athlete with and without a knee brace. Results: Prophylactic knee bracing increased the hip flexion angle at peak GRF by 5.56° ( P < .001), knee flexion angle at peak GRF by 4.75° ( P = .001), and peak hip extension moment by 0.44 N·m/kg ( P < .001). Bracing also increased the peak hip negative power by 4.89 W/kg ( P = .002) and hip negative work by 0.14 J/kg ( P = .001) but did not result in significant differences in the energetics of the knee and ankle. No differences in peak GRFs and peak knee extension moment were observed with bracing. Conclusion: The application of a prophylactic knee brace resulted in improvements in important biomechanical factors associated with the risk of ACL injuries. Clinical Relevance: Prophylactic knee braces may help reduce the risk of noncontact knee injuries in recreational and professional athletes while playing sports. Further studies should investigate different types of prophylactic knee braces in conjunction with existing training interventions so that the sports medicine community can better assess the effectiveness of prophylactic knee bracing.

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Obese Youth Demonstrate Altered Landing Knee Mechanics Unrelated to Lower-Extremity Peak Torque When Compared With Healthy Weight Youth

Journal of Applied Biomechanics ◽

10.1123/jab.2020-0013 ◽

2020 ◽

pp. 1-9

Author(s):

Matthew S. Briggs ◽

Claire Spech ◽

Rachel King ◽

Mike McNally ◽

Matthew Paponetti ◽

...

Keyword(s):

Lower Extremity ◽

Knee Flexion ◽

Peak Torque ◽

Knee Extension ◽

Knee Flexion Angle ◽

Healthy Weight ◽

Knee Mechanics ◽

Landing Mechanics ◽

Peak Knee ◽

Hip Extension

Obese (OB) youth demonstrate altered knee mechanics and worse lower-extremity performance compared with healthy weight (HW) youth. Our objectives were to compare sagittal plane knee landing mechanics between OB and HW youth and to examine the associations of knee and hip extension peak torque with landing mechanics in OB youth. Twenty-four OB and 24 age- and sex-matched HW youth participated. Peak torque was measured and normalized to leg lean mass. Peak knee flexion angle and peak internal knee extension moment were measured during a single-leg hop landing. Paired t tests, Pearson correlation coefficients, and Bonferroni corrections were used. OB youth demonstrated worse performance and lower knee extension (OB: 12.76 [1.38], HW: 14.03 [2.08], P = .03) and hip extension (OB: 8.59 [3.13], HW: 11.10 [2.89], P = .005) peak torque. Furthermore, OB youth demonstrated lower peak knee flexion angles (OB: 48.89 [45.41 to 52.37], HW: 56.07 [52.59 to 59.55], P = .02) and knee extension moments (OB: −1.73 [−1.89 to −1.57], HW: −2.21 [−2.37 to −2.05], P = .0001) during landing compared with HW youth. Peak torque measures were not correlated with peak knee flexion angle nor internal knee extension moment during landing in either group (P > .01). OB youth demonstrated altered landing mechanics compared with HW youth. However, no associations among peak torque measurements and knee landing mechanics were present.

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Quadriceps Neuromuscular Function and Jump-Landing Sagittal-Plane Knee Biomechanics After Anterior Cruciate Ligament Reconstruction

Journal of Athletic Training ◽

10.4085/1062-6050-306-16 ◽

2018 ◽

Vol 53 (2) ◽

pp. 135-143 ◽

Cited By ~ 18

Author(s):

Sarah H. Ward ◽

J. Troy Blackburn ◽

Darin A. Padua ◽

Laura E. Stanley ◽

Matthew S. Harkey ◽

...

Keyword(s):

Knee Flexion ◽

Sagittal Plane ◽

Neuromuscular Function ◽

Knee Extension ◽

Spinal Reflex ◽

Flexion Angle ◽

Voluntary Activation ◽

Knee Flexion Angle ◽

Jump Landing ◽

Peak Knee

Context: Aberrant biomechanics may affect force attenuation at the knee during dynamic activities, potentially increasing the risk of sustaining a knee injury or hastening the development of osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Impaired quadriceps neuromuscular function has been hypothesized to influence the development of aberrant biomechanics. Objective: To determine the association between quadriceps neuromuscular function (strength, voluntary activation, and spinal-reflex and corticomotor excitability) and sagittal-plane knee biomechanics during jump landings in individuals with ACLR. Design: Cross-sectional study. Setting: Research laboratory. Patients or Other Participants: Twenty-eight individuals with unilateral ACLR (7 men, 21 women; age = 22.4 ± 3.7 years, height = 1.69 ± 0.10 m, mass = 69.4 ± 10.1 kg, time postsurgery = 52 ± 42 months). Main Outcome Measure(s): We quantified quadriceps spinal-reflex excitability via the Hoffmann reflex normalized to maximal muscle response (H : M ratio), corticomotor excitability via active motor threshold, strength as knee-extension maximal voluntary isometric contraction (MVIC), and voluntary activation using the central activation ratio (CAR). In a separate session, sagittal-plane kinetics (peak vertical ground reaction force [vGRF] and peak internal knee-extension moment) and kinematics (knee-flexion angle at initial contact, peak knee-flexion angle, and knee-flexion excursion) were collected during the loading phase of a jump-landing task. Separate bivariate associations were performed between the neuromuscular and biomechanical variables. Results: In the ACLR limb, greater MVIC was associated with greater peak knee-flexion angle (r = 0.38, P = .045) and less peak vGRF (r = −0.41, P = .03). Greater CAR was associated with greater peak internal knee-extension moment (ρ = −0.38, P = .045), and greater H : M ratios were associated with greater peak vGRF (r = 0.45, P = .02). Conclusions: Greater quadriceps MVIC and CAR may provide better energy attenuation during a jump-landing task. Individuals with greater peak vGRF in the ACLR limb possibly require greater spinal-reflex excitability to attenuate greater loading during dynamic movements.

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Preparatory Knee Flexion-Extension Movements Enhance Rapid Sidestepping Performance in Collegiate Basketball Players

Frontiers in Sports and Active Living ◽

10.3389/fspor.2021.670649 ◽

2021 ◽

Vol 3 ◽

Author(s):

Masahiro Fujimoto ◽

Eri Uchida ◽

Akinori Nagano ◽

Mark W. Rogers ◽

Tadao Isaka

Keyword(s):

Lower Limb ◽

Knee Flexion ◽

Knee Extension ◽

Movement Initiation ◽

Basketball Players ◽

Step Initiation ◽

Limb Loading ◽

Flexion Extension ◽

Collegiate Basketball ◽

Lift Off

Lower-limb weight-bearing load distribution in stationary standing influences the timing of rapid first step initiation of importance for functional movement activities and agility performance in sports. This study investigated the effect of pre-step lower-limb loading and unloading with preparatory knee flexion-extension movements on sidestepping performance in fifteen male collegiate basketball players. Participants performed two-choice (step limb) reaction time sidestepping under two conditions: without preparatory movements before the go cue (no-prep–NP) and with continuous alternating knee extension and flexion movements (prep–P). The reaction signal was provided at the beginning of knee extension and flexion and during these movements which corresponded with the largest and smallest loading instants and the transition states between those instants. Sidestepping performance was assessed with three-dimensional kinematic data and ground reaction forces. Step initiation onset time was significantly faster by 13–15% than the NP condition when initiated in the knee flexion phase (p ≤ 0.028, r ≥ 0.70), whereas step-limb unloading interval from step initiation to step lift-off was significantly faster by 12–15% in the knee extension phase (p ≤ 0.01, r ≥ 0.74). The preparatory movements significantly shortened step lift-off by 10–12% (p ≤ 0.013, r ≥ 0.73) and step duration by 17–21% (p < 0.001, r ≥ 0.85) with 19–22% faster step velocity (p < 0.001, r ≥ 0.84), which resulted in 14–15% shorter overall time to step landing (p < 0.001, r ≥ 0.84), irrespective of the loading phases. These results indicated that lower-limb loading with pre-step knee flexion facilitated faster step initiation, while lower-limb unloading with knee extension facilitated faster step-limb unloading, both resulting in faster step lift-off. Bilateral knee flexion-extension movements as a preparatory action could be utilized by invasion sports players to facilitate reactive stepping performance for more effective movement initiation.

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Measuring Clinically Relevant Knee Motions With A Self-Calibrated Wearable Sensor

10.1101/309328 ◽

2018 ◽

Author(s):

Todd J. Hullfish ◽

Feini Qu ◽

Brendan D. Stoeckl ◽

Peter M. Gebhard ◽

Robert L. Mauck ◽

...

Keyword(s):

Motion Capture ◽

Knee Flexion ◽

Low Cost ◽

Calibration Procedure ◽

Knee Extension ◽

Strongly Correlated ◽

Wearable Sensor ◽

Additional Equipment ◽

Peak Knee ◽

Rms Error

AbstractLow-cost sensors provide a unique opportunity to continuously monitor patient progress during rehabilitation; however, these sensors have yet to demonstrate the fidelity and lack the calibration paradigms necessary to be viable tools for clinical research. Therefore, the purpose of this study was to validate a low-cost wearable sensor that accurately measured peak knee extension during clinical exercises and needed no additional equipment for calibration. Knee flexion was quantified using a 9-axis motion sensor and directly compared to motion capture data. Peak extension values during seated knee extensions were accurate within 5 degrees across all subjects (RMS error: 2.6 degrees, P = 0.29) but less accurate during sit-to-stand exercises (RMS error: 16.6 degrees, P = 0.48). Knee flexion during gait strongly correlated (0.84 ≤ rxy ≤ 0.99) with motion capture measurements but demonstrated average errors of 10 degrees. This study demonstrated a low-cost sensor that satisfied our criteria: a simple calibration procedure resulting in accurate measures of joint function during clinical exercises, making it a feasible tool for continuous patient monitoring to guide regenerative rehabilitation.

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Knee Strength Capabilities and Slip Severity

Journal of Applied Biomechanics ◽

10.1123/jab.25.2.140 ◽

2009 ◽

Vol 25 (2) ◽

pp. 140-148 ◽

Cited By ~ 9

Author(s):

Sarah A. Wyszomierski ◽

April J. Chambers ◽

Rakié Cham

Keyword(s):

Muscle Strength ◽

Knee Flexion ◽

Age Groups ◽

Peak Torque ◽

Knee Extension ◽

Health Concern ◽

Young Males ◽

Motion Data ◽

Flexion Extension ◽

Muscle Moments

Slips and falls are a serious public health concern in older populations. Reduced muscle strength is associated with increased age and fall incidence. Understanding the relationships between specific joint muscle strength characteristics and propensity to slip is important to identify biomechanical factors responsible for slip-initiated falls and to improve slip/fall prevention programs. Knee corrective moments generated during slipping assist in balance recovery. Therefore, the study goal was to investigate the relationship between knee flexion/extension strength and slip severity. Isometric knee flexion/extension peak torque and rate of torque development (RTD) of the slipping leg were measured in 29 young and 28 older healthy subjects. Motion data were collected for an unexpected slip during self-paced walking. Peak slip velocity (PSV) of the slipping heel served as a slip severity measure. Within-sex and age group regressions relating gait speed-controlled PSV to strength of the slipping leg revealed significant inverse PSV-knee extension peak torque and PSV-knee flexion/extension RTD relationships in young males only. Differences in PSV-strength relationships between sex and age groups may be caused by greater ranges of strength capabilities in young males. In conclusion, the ability to generate higher, more rapid knee flexion/extension muscle moments (greater peak torque/RTD) may assist in recovery from severe slips.

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Does Chronic Ankle Instability Influence Knee Biomechanics of Females during Inverted Surface Landings?

International Journal of Sports Medicine ◽

10.1055/s-0044-102130 ◽

2018 ◽

Vol 39 (13) ◽

pp. 1009-1017 ◽

Cited By ~ 2

Author(s):

Yumeng Li ◽

Jupil Ko ◽

Marika Walker ◽

Cathleen Brown ◽

Julianne Schmidt ◽

...

Keyword(s):

Internal Rotation ◽

Knee Flexion ◽

Sagittal Plane ◽

Ankle Instability ◽

Knee Extension ◽

Chronic Ankle Instability ◽

Initial Contact ◽

Knee Biomechanics ◽

Peak Knee ◽

Eccentric Work

AbstractThe primary purpose of the study was to determine whether atypical knee biomechanics are exhibited during landing on an inverted surface. A seven-camera motion analysis system and two force plates were used to collect lower extremity biomechanics from two groups of female participants: 21 subjects with chronic ankle instability (CAI) and 21 with pair-matched controls. Subjects performed ten landings onto inverted and flat platforms on the CAI/matched and non-test limbs, respectively. Knee and ankle joint angles, joint angular displacements, joint moments and eccentric work were calculated during the landing phase and/or at the initial contact. Paired t-tests were used to compare between-group differences (p<0.05). We observed that CAI group displayed a significantly increased knee flexion angle, knee flexion displacement, peak knee extension moment and internal rotation moment, and eccentric work in the sagittal plane, possibly due to altered ankle biomechanics. Participants with CAI employed some compensatory strategy to improve their ankle and postural stability during landing onto the tilted surface. The increased knee extension and internal rotation moments of CAI participants could potentially result in a greater ACL loading. In future studies, it may be worthwhile to measure or estimate the ACL loading to confirm whether CAI could relate to the mechanism of ACL injury.

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Repeated Kicking Actions in Karate: Effect on Technical Execution in Elite Practitioners

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2015-0162 ◽

2016 ◽

Vol 11 (3) ◽

pp. 363-369 ◽

Cited By ~ 8

Author(s):

Federico Quinzi ◽

Valentina Camomilla ◽

Alberto Di Mario ◽

Francesco Felici ◽

Paola Sbriccoli

Keyword(s):

Knee Flexion ◽

Muscle Activation ◽

Vastus Lateralis ◽

Linear Regression Analysis ◽

Knee Kinematics ◽

Rectus Femoris ◽

Knee Extension ◽

Median Frequency ◽

Flexion Extension ◽

Hip Abduction

Purpose:Training in martial arts is commonly performed by repeating a technical action continuously for a given number of times. This study aimed to investigate if the repetition of the task alters the proper technical execution, limiting the training efficacy for the technical evaluation during competition. This aim was pursued analyzing lower-limb kinematics and muscle activation during repeated roundhouse kicks.Methods:Six junior karate practitioners performed continuously 20 repetitions of the kick. Hip and knee kinematics and sEMG of vastus lateralis, biceps (BF), and rectus femoris were recorded. For each repetition, hip abduction–adduction and flexion–extension and knee flexion–extension peak angular displacements and velocities, agonist and antagonist muscle activation were computed. Moreover, to monitor for the presence of myoelectric fatigue, if any, the median frequency of the sEMG was computed. All variables were normalized with respect to their individual maximum observed during the sequence of kicks. Linear regressions were fitted to each normalized parameter to test its relationship with the repetition number.Results:Linear-regression analysis showed that, during the sequence, the athletes modified their technique: Knee flexion, BF median frequency, hip abduction, knee-extension angular velocity, and BF antagonist activation significantly decreased. Conversely, hip flexion increased significantly.Conclusions:Since karate combat competitions require proper technical execution, training protocols combining severe fatigue and technical actions should be carefully proposed because of technique adaptations. Moreover, trainers and karate masters should consider including specific strength exercises for the BF and more generally for knee flexors.

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