Knee Flexion Range Of Motion Research Articles

Sex-based differences in landing mechanics vary between the drop vertical jump and stop jump

The purpose of the present study was to compare landing mechanics between the stop jump (SJ) and drop vertical jump (DVJ) and to compare sex-based differences in landing mechanics between tasks. 50 healthy recreational athletes were recruited and each participant completed seven SJs and seven DVJs. Peak knee flexion and abduction angle, knee flexion and ab/adduction range of motion (ROM), peak vertical and posterior ground reaction force (GRF), peak internal knee extension and knee adduction moment were computed for the dominant limb during the first landing of both tasks. A two-way ANOVA was used to determine the effects of and interactions between sex (men vs women) and task (SJ vs DVJ) for each outcome. There was an interaction for peak vertical GRF (p = 0.024), knee flexion ROM (p = 0.027), knee ab/adduction ROM (p = 0.047), and peak knee flexion (p = 0.034) and adduction (p = 0.012) moment. The SJ resulted in smaller vertical GRFs, larger posterior GRFs, and larger peak internal knee adduction moments relative to the DVJ (all p < 0.002). Women landed with larger peak knee abduction angles, larger internal knee adduction moments, and smaller knee extension moments relative to men (p = 0.001–0.026). Overall, as the SJ resulted in larger posterior GRFs and internal knee adduction moments, this task produced movements which resemble most anterior cruciate ligament (ACL) injuries and are risk factors for ACL injuries. As the SJ produced more sex-based differences, it may be better suited than the DVJ for ACL injury risk screening. This study therefore stressed the importance of selecting an appropriate landing task for ACL injury prevention research and clinical return to sport assessment.

The relationship between the deep squat movement and the hip, knee and ankle range of motion and muscle strength.

[Purpose] We examined and clarified the relationship between the maximum squat depth and the range of motion of the ankle, knee, and hip joints, and the knee and hip muscle strength. [Participants and Methods] Nine healthy males participated in this study and performed a deep squat with the upper extremities raised; the movement was analyzed by two-dimensional motion analysis. We measured the ankle dorsiflexion, hip flexion, and knee flexion ranges of motion, as well as the knee extension and hip flexion muscle strengths and analyzed the relationship between the squatting motion, the range of motion, and the muscle strength of each joint. [Results] The right ankle dorsiflexion range of motion was a significant predictor of the ankle dorsiflexion angle on both sides. The right knee flexion range of motion was a significant predictor of the knee flexion angle, and the left knee flexion range of motion was a significant predictor of the trunk anterior tilt angle on both sides. The right ankle dorsiflexion range of motion was a significant predictor of the right hip flexion angle and vice versa. [Conclusion] This study reveals that movement on one side affects contralateral movement, which is important when evaluating the deep squat motion as a functional test.

Comparison of effectiveness of hold-relax technique and maitlandfs mobilization in improving range of motion in posttraumatic stiffness of knee joint

Aims: This study aims to compare the effectiveness of Hold-Relax technique and Maitland's Mobilization in improving range of motion (ROM) in posttraumatic stiffness of knee joint. Materials and Methods: This was a randomized interventional comparative study with 30 subjects with posttraumatic stiffness of knee joint with restricted range of knee flexion were randomly allotted into two groups: Group A was given Hold-Relax technique and Group B was given Maitland's Mobilization consisted of Grade 3 posterior glide along with paraffin wax bath and isometric exercises of quadriceps and hamstring as a common baseline treatment for 5 days per week for 4 weeks. The baseline outcome measure was active knee flexion ROM measured by universal Goniometer before and after 4 weeks interventions. Results: Statistical analysis of data was done using paired t-test and unpaired t-test. Paired t-test showed that statistically significant increase in active knee flexion ROM in both the groups. On comparing by unpaired t-test it was found that both the techniques are equally effective in improving ROM. Conclusion: Both the Hold-Relax technique and Maitland's Mobilization are equally effective, in improving the knee flexion ROM.

Extrinsic feedback from a feedback device promotes the learning of range of motion measurements.

[Purpose] Although it is widely recognized that feedback is important for skill acquisition or improvement, feedback is not completely utilized in physical therapy education. Therefore, we aimed to verify the effect of extrinsic feedback from a feedback device on proficiency in range of motion measurements by a universal goniometer. [Participants and Methods] The participants included 22 physical therapy students who were randomly assigned to feedback (n=11) and non-feedback groups (n=11). The passive right knee flexion range of motion was set as the measurement task. The experiment consisted of a pretest phase, practice trials, and a posttest phase. In the pretest phase, all participants conducted three measurements without extrinsic feedback. Extrinsic feedback related to measurement error from a device was given only to the feedback group. The posttest was conducted 24 hours after the practice trials with the same content as that in the pretest. [Results] The improvement rate from pretest to posttest was greater in the feedback group than in the non-feedback group. The results indicated that the measurement error decreases with extrinsic measurement error-related feedback during practice. [Conclusion] The utilization of extrinsic feedback from a feedback device is effective for enhancing range of motion measurement skills.

What are the Benefits and Risks Associated with Changing Foot Strike Pattern During Running? A Systematic Review and Meta-analysis of Injury, Running Economy, and Biomechanics.

Running participation continues to increase. The ideal strike pattern during running is a controversial topic. Many coaches and therapists promote non-rearfoot strike (NRFS) running with a belief that it can treat and prevent injury, and improve running economy. The aims of this review were to synthesise the evidence comparing NRFS with rearfoot strike (RFS) running patterns in relation to injury and running economy (primary aim), and biomechanics (secondary aim). Systematic review and meta-analysis. Consideration was given to within participant, between participant, retrospective, and prospective study designs. MEDLINE, EMBASE, CINAHL, and SPORTDiscus. Fifty-three studies were included. Limited evidence indicated that NRFS running is retrospectively associated with lower reported rates of mild (standard mean difference (SMD), 95% CI 3.25, 2.37-4.12), moderate (3.65, 2.71-4.59) and severe (0.93, 0.32-1.55) repetitive stress injury. Studiesprospectively comparing injury risk between strike patterns are lacking. Limited evidence indicated that running economy did not differ between habitual RFS and habitual NRFS runners at slow (10.8-11.0km/h), moderate (12.6-13.5km/h), and fast (14.0-15.0km/h) speeds, and was reduced in the immediate term when an NRFS-running pattern was imposed on habitual RFS runners at slow (10.8km/h; SMD = - 1.67, - 2.82 to - 0.52) and moderate (12.6km/h; - 1.26, - 2.42 to - 0.10) speeds. Key biomechanical findings, consistently including both comparison between habitual strike patterns and following immediate transition from RFS to NRFS running, indicated that NRFS running was associated with lower average and peak vertical loading rate (limited-moderate evidence; SMDs = 0.72-2.15); lower knee flexion range of motion (moderate-strong evidence; SMDs = 0.76-0.88); reduced patellofemoral joint stress (limited evidence; SMDs = 0.63-0.68); and greater peak internal ankle plantar flexor moment (limited evidence; SMDs = 0.73-1.33). The relationship between strike pattern and injury risk could not be determined, as current evidence is limited to retrospective findings. Considering the lack of evidence to support any improvements in running economy, combined with the associated shift in loading profile (i.e., greater ankle and plantarflexor loading) found in this review, changing strike pattern cannot be recommended for an uninjured RFS runner. CRD42015024523.

Influence of Foot-Landing Positions at Initial Contact on Knee Flexion Angles for Single-Leg Drop Landings

ABSTRACTPurpose: Small knee flexion angles are associated with increased non-contact anterior cruciate ligament (ACL) injury risks. The purpose of this study was to provide insights into how ankle plantar flexion angles influenced knee flexion angles at initial contact during single-leg drop landings. Method: Thirteen male recreational basketball players performed single-leg drop landings from a 30-cm high platform using three randomized foot-landing positions (natural, fore-foot, and flat-foot). A motion capture system and a force plate were used to measure lower extremity kinematics and vertical ground reaction force (VGRF). A one-way repeated measures Analysis of Variance and the Friedman test were conducted (α = .05). Results: Foot-landing position had a significant effect on knee flexion angles at initial contact (p < .001). As compared to flat-foot landings (18° (SD 5°), significantly smaller knee flexion angles were found for natural (mean 12° (SD 5°), p = .004) and fore-foot landings (mean 12° (SD 3°), p = .001). There was however significantly smaller knee flexion range of motion in flat-foot landings (mean 42° (SD 3°), as compared to natural landings (mean 48° (SD 4°) (p < .001). Flat-foot landings also resulted in a 1.4 times higher maximum VGRF than fore-foot landings (p < .001) and 1.3 times higher than natural landings (p = .005). Conclusions: Natural and fore-foot landings are better for force absorption but are associated with smaller knee flexion angles at initial contact. These findings have important implications for non-contact ACL injuries.

Knee Biomechanical Deficits During a Single-Leg Landing Task Are Addressed With Neuromuscular Training in Anterior Cruciate Ligament-Reconstructed Athletes.

Faulty neuromuscular and biomechanical deficits of the knee are nearly ubiquitous in athletes after anterior cruciate ligament (ACL) reconstruction (ACLR). Knee biomechanical deficits are directly associated with an increased risk of second ACL injury, which typically occurs during a sports-related movement on a single limb. To date, the biomechanical effects of a neuromuscular training (NMT) program on knee biomechanics during a single-leg landing task have not been investigated. Prospective Cohort Study. Controlled laboratory setting. Eighteen ACLR and 10 control athletes. Neuromuscular training. Knee kinematics and kinetics. There were no significant interactions of session and limb (P > 0.05) for the athletes with ACLR after training. However, there were several significant main effects of session (P < 0.05) for knee kinematics and kinetics during the single-leg landing task. After training, the athletes with ACLR landed with greater knee flexion angles, decreased knee abduction angles, increased knee flexion range of motion, and decreased knee excursion. Also, the ACLR athletes landed with lower knee flexion moments, greater knee adduction moments, and lower peak vertical ground reaction force. Post-training comparison of the ACLR and control cohorts found no significant interactions of group and limb (P > 0.05) and only a significant main effect of group (P < 0.05) for frontal plane knee angle at initial contact. The athletes with ACLR landed with greater knee adduction angles than the control group. Deficits in knee biomechanics that are associated with an increased risk of ACL injury are attenuated after completion of this NMT program.

The effect of mobilization with movement on pain and function in patients with knee osteoarthritis: a randomized double-blind controlled trial

BackgroundFew studies have investigated the effects of mobilization with movement (MWM) in patients with knee osteoarthritis (OA) compared to other procedures. Sham procedures are generally more appropriate control than using no or usual treatments. Moreover, studies investigating the widespread hypoalgesic effects of MWM in patients with knee OA are lacking. The aim was to investigate the effect of MWM on function and pain in patients with knee OA compared to sham MWM.MethodsThis is a randomized double-blind (patients and assessor) controlled trial. Forty adult patients with knee OA of grade II and above were recruited to receive either MWM treatment or sham MWM for the knee. The outcome measures included the following: a visual analogue scale (VAS) for pain, the pressure pain threshold (PPT) test, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index, the timed up and go (TUG) test, knee strength and knee range of motion (ROM). The measurements were taken at baseline, immediately after intervention and 2 days later.ResultsCompared with sham MWM, MWM resulted in greater immediate improvement in pain [mean difference (95% CI): − 2.2 (− 2.8, − 1.6)], PPT at both the knee [176 (97, 254)] and shoulder [212 (136, 288)], TUG time [− 1.6 (− 2.1, − 1.1)], knee flexor strength [2.0 (1.3, 2.7)] and extensor strength [5.7 (4.1, 7.2)] and knee flexion ROM [12.8 (9.6, 15.9)] (all, p < 0.001) but not knee extension ROM [− 0.8 (− 1.6, 0.1)] (p = 0.067). After 2 days of intervention, patients who received MWM also demonstrated a greater improvement in pain [− 1.0 (− 1.8, − 0.1)], PPT at the shoulder [107 (40, 175)], TUG time [− 0.9 (− 1.4, − 0.4)], knee flexor strength [0.9 (0.2, 1.7)] and extensor strength [2.9 (2.1, 3.9)] and knee flexion ROM [8.3 (4.7, 11.9)] (all, p ≤ 0.026). However, WOMAC scores and knee extension ROM showed no evidence of change at any stage after intervention (p ≥ 0.067).ConclusionsMWM provided superior benefits over sham MWM in terms of local and widespread pain, physical function (walking), knee flexion and extension muscle strength and knee flexion ROM for at least 2 days in patients with knee OA.Trial registrationClinicalTrials.gov (NCT02865252), registered on August 12, 2016.

Additional effect of neuromuscular electrical stimulation on knee extension lag, pain and knee range of motion in immediate postsurgical phase (0–2 weeks) in primary total knee arthroplasty patient

There are various studies on younger adults which have shown that neuromuscular electrical stimulation (NMES), at sufficient intensities, combined with active exercises had better improvement in muscle strength and functional performance than exercises alone. But very limited research is available for giving NMES in the early acute stages post total knee arthroplasty (TKA). So, the short-term effect of NMES had not yet been researched upon widely. As there were conflicting evidences in giving NMES post TKA, this study was proposed to assess the short-term effect of early NMES on knee joint pain, range of motion (ROM) and extension lag on patients undergoing bilateral TKA. The study included 28 bilateral TKA patients following osteoarthritis (OA) knee within the age group of 50-75 years (60.82±5.69). The knees of 28 bilaterally operated patients were randomly divided into two groups; 1 knee was allocated in the experimental group and the other knee of the same patient became the control. The experimental group was given NMES with exercises, while the control group was given only exercises for 7 days. The patients were asked to continue to follow exercises even after the discharge, i.e., beyond 7 days. The patients were measured for pain; knee flexion ROM and extensor lag both before and after intervention. There was a significant improvement in pain, knee ROM and extensor lag post intervention P<0.05 in both the groups. But there was no significant difference between the groups with respect to pain, knee ROM and extensor lag, P>0.05. The NMES and exercises worked equally in case of patients operated for TKA. Hence our results concluded that there was no additional effect of NMES on extensor lag, knee ROM and pain when applied for 7 days in patients operated with TKA.

Acute effects of foam rolling on passive stiffness, stretch sensation and fascial sliding: A randomized controlled trial

PurposeFoam Rolling (FR), aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are poorly understood. The aim of the present study was to further elucidate the acute, systemic and tissue-specific responses evoked by FR. MethodsIn a crossover study, 16 (34 ± 6y, 6f) participants received all of the following interventions in a random order: a) 2 × 60 seconds of FR at the anterior thigh, b) 2 × 60 seconds of passive static stretching of the anterior thigh (SS), and c) no intervention (CON). Maximal active and passive knee flexion range of motion (ROM), passive stiffness, sliding of fascial layers, as well as knee flexion angle of first subjectively perceived stretch sensation (FSS) were evaluated before and directly after each intervention. ResultsFlexibility increased only after, FR (active (+1.8 ± 1.9%) and passive ROM (+3.4 ± 2.7%), p = .006, respectively) and SS (passive ROM (+3.2 ± 3.5%), p = .002). Angle of FSS was altered following FR (+4.3° (95% CI: 1.4°–7.2°)) and SS (+6.7° (3.7°–9.6°)), while tissue stiffness remained unchanged after any intervention compared to baseline. Movement of the deepest layer (−5.7 mm (−11.3 mm to −0.1 mm)) as well as intrafascial sliding between deep and superficial layer (−4.9 mm (−9.mm to −0.7 mm)) decreased only after FR. ConclusionFR improved knee flexion ROM without altering passive stiffness, but modified the perception of stretch as well as the mobility of the deep layer of the fascia lata. The mechanisms leading to altered fascial sliding merit further investigation.

Lower limb kinematics and hip extensors strengths are associated with performance of runners at high risk of injury during the modified Star Excursion Balance Test

BackgroundReduced trunk and lower limb movement and hip and trunk muscles weakness may compromise the athletes’ performance on the modified Star Excursion Balance Test (mSEBT). ObjectiveTo investigate the relationship of trunk and lower limb kinematics and strength with the performance on the mSEBT of runners at high risk of injury. MethodsThirty-nine runners performed the mSEBT with the dominant limb as the support limb. An Inertial System was used to capture the trunk, hip, knee and ankle movement during the mSEBT. A handheld dynamometer was used to measure the strength of trunk extensors and lateral flexors muscles, and hip extensors, lateral rotators and abductors of the support limb. Multiple regressions were used to investigate if trunk and lower limbs kinematics and trunk and hip muscles strength are associated with performance during the mSEBT. ResultsReduced hip flexion and greater knee flexion range of motion (ROM) were associated with anterior reach in the mSEBT (r2=0.45; p<.001), greater hip flexion ROM was associated with posteromedial reach (r2=0.15; p=.012) and greater knee flexion ROM was associated with posterolateral reach (r2=0.23; p<.001). Hip extensor strength was associated with posteromedial (r2=0.14; p=.017), posterolateral (r2=0.10; p=.038) and composite reaches (r2=0.16; p=.009). ConclusionHip and knee kinematics in the sagittal plane explained 15–45% of the runners’ performance on the mSEBT and hip extensor strength explained 10–16% of the mSEBT performance. These findings provide useful information on the contribution of joints kinematics and strength when evaluating dynamic postural control in runners at high risk of injury.

Computer interactions during walking workstation use moderately affects spatial-temporal gait characteristics

BackgroundDue to increased sedentary workstyles, active workstations have shown the ability to increase activity while only moderately affecting work ability. However, previous examinations have not examine fine motor mousing tasks on tripping descriptors. Research QuestionWhat affect do mousing tasks of varying target size have on tripping descriptors during walking workstation use? MethodsThree-dimensional kinematic data were collected while participants used a walking workstation completing one baseline and three mousing conditions of varying target sizes. ResultsTarget size main effects (p < 0.001) detected decreased stride length in all experimental conditions, which were supported by moderate effect sizes, and decreased stance width and time in double limb support (p < 0.001 for both comparisons). Stance width differences resulted in large effect sizes between baseline and all conditions, while only moderate effect sizes were observed between time in double limb support in baseline compared to all conditions. No changes in knee flexion range of motion were observed in response to target size (p = 0.278). SignificanceThese results indicate that walking workstation users shorten their stride length and decrease their base of support while completing mousing tasks. The placement of the upper extremities on the workstation desk likely acted as the primary mechanism to increase stability. It is concluded that performing mousing tasks of varying target size using a walking workstation does not pose greater risk for adverse gait events.

My kinematics as a template to decode your actions: the role of motor resonance in intention prediction

The aim of the present study is to compare sagittal gait kinematics of ankle, knee and hip joints between subjects with unicondylar and total knee arthroplasty and age matched healthy controls. Since unicondylar knee replacement is a less invasive procedure, which more closely preserves knee joint anatomy, we hypothesized that one year post unicondylar knee arthroplasty patients would demonstrate more normal gait patterns than patients with total knee arthroplasty.Do unicondylar and total knee arthroplasty patients display similar gait kinematics one year after surgery?Fourteen subjects (8 posterior stabilized and 6 medial unicondylar knee replacements) that were one year post surgery, and 6 healthy control subjects underwent a 3D gait analysis and a physical examination (range of motion, muscle strength). Statistical parametric mapping was used to compare gait kinematics of the lower limbs between groups. Additionally, differences in peak angles and clinical outcomes were assessed using a one-way ANOVA between subjects analysis.Both knee replacement groups showed reduced knee flexion range of motion and reduced muscle strength at the operated leg compared to the control group. Subjects with TKA demonstrated reduced knee flexion at loading response and midstance of the gait cycle. Both UKA and TKA demonstrated significantly less knee flexion during swing.The results of this study demonstrate arthroplasty-specific differences in muscle strength, range of motion and gait kinematics of the lower limb one year after knee surgery. Future planning of post-surgery follow-up should addresses these arthroplasty-specific weaknesses and gait deviations.

Influence of Foam Rolling Velocity on Knee Range of Motion and Tissue Stiffness: A Randomized, Controlled Crossover Trial.

Foam rolling (FR) increases joint range of motion (RoM), but the optimal training parameters are unknown. To investigate the effect of FR velocity on RoM and tissue stiffness. Randomized, controlled crossover trial. University. A total of 17 healthy, physically active adults (10 females; 25 [2]y). (1)Four 45-second high-velocity FR of the anterior thigh (FAST-FR), (2) four 45-second slow-velocity FR of the anterior thigh (SLOW-FR), and (3)inactive control. Maximal knee-flexion RoM (ultrasonic movement analysis) and anterior thigh tissue stiffness (semielectronic tissue compliance meter) assessed pre, immediately post (T0), as well as 5 (T5) and 10 (T10) minutes postintervention. Statistical analysis included Friedman tests with adjusted post hoc comparisons (Wilcoxon tests). According to omnibus testing, RoM remained unchanged in all 3 conditions and at all time points (P > .05), while differences were found for tissue stiffness (P < .05). Post hoc tests revealed significant decreases following FAST-FR (T5: -17%, T10: -24%; P < .05) and SLOW-FR (T10: -15%; P < .05). The observed stiffness changes were significant in comparison with control (P < .01), but no difference was found between the 2 FR conditions (P > .05). FR of the anterior thigh decreases myofascial stiffness regardless of velocity. The lack of effects on RoM contrasts findings of recent literature and warrants further investigation.

Lower extremity gait kinematics outcomes after knee replacement demonstrate arthroplasty-specific differences between unicondylar and total knee arthroplasty: A pilot study

BackgroundThe aim of the present study is to compare sagittal gait kinematics of ankle, knee and hip joints between subjects with unicondylar and total knee arthroplasty and age matched healthy controls. Since unicondylar knee replacement is a less invasive procedure, which more closely preserves knee joint anatomy, we hypothesized that one year post unicondylar knee arthroplasty patients would demonstrate more normal gait patterns than patients with total knee arthroplasty. Research questionDo unicondylar and total knee arthroplasty patients display similar gait kinematics one year after surgery? MethodsFourteen subjects (8 posterior stabilized and 6 medial unicondylar knee replacements) that were one year post surgery, and 6 healthy control subjects underwent a 3D gait analysis and a physical examination (range of motion, muscle strength). Statistical parametric mapping was used to compare gait kinematics of the lower limbs between groups. Additionally, differences in peak angles and clinical outcomes were assessed using a one-way ANOVA between subjects analysis. ResultsBoth knee replacement groups showed reduced knee flexion range of motion and reduced muscle strength at the operated leg compared to the control group. Subjects with TKA demonstrated reduced knee flexion at loading response and midstance of the gait cycle. Both UKA and TKA demonstrated significantly less knee flexion during swing. SignificanceThe results of this study demonstrate arthroplasty-specific differences in muscle strength, range of motion and gait kinematics of the lower limb one year after knee surgery. Future planning of post-surgery follow-up should addresses these arthroplasty-specific weaknesses and gait deviations.

A Bayesian Network approach to study the relationships between several neuromuscular performance measures and dynamic postural control in futsal players

PurposeThe purpose of this study was to analyse the relationship between several parameters of neuromuscular performance with dynamic postural control using a Bayesian Network Classifiers (BN) based analysis.MethodsThe y-balance test (measure of dynamic postural control), isokinetic (concentric and eccentric) knee flexion and extension strength, isometric hip abduction and adduction strength, lower extremity joint range of motion (ROM) and core stability were assessed in 44 elite male futsal players. A feature selection process was carried out before building a BN (using the Tabu search algorithm) for each leg. The BN models built were used to make belief updating processes to study the individual and concurrent contributions of the selected parameters of neuromuscular performance on dynamic postural control.ResultsThe BNs generated using the selected features by the algorithms correlation attribute evaluator and chi squared reported the highest evaluation criteria (area under the receiver operating characteristic curve [AUC]) for the dominant (AUC = 0.899) and non-dominant (AUC = 0.879) legs, respectively.ConclusionsThe BNs demonstrated that performance achieved in the y-balance test appears to be widely influenced by hip and knee flexion and ankle dorsiflexion ROM measures in the sagittal plane, as well as by measures of static but mainly dynamic core stability in the frontal plane. Therefore, training interventions aimed at improving or maintaining dynamic postural control in elite male futsal players should include, among other things, exercises that produce ROM scores equal or higher than 127° of hip flexion, 132.5° of knee flexion as well as 34° and 30.5° of ankle dorsiflexion with the knee flexed and extended, respectively. Likewise, these training interventions should also include exercises to maintain or improve both the static and dynamic (medial-lateral plane) core stability so that futsal players can achieve medial radial error values lower than 6.69 and 8.79 mm, respectively.

Foam Rolling as a Recovery Tool Following Eccentric Exercise: Potential Mechanisms Underpinning Changes in Jump Performance.

PurposeRecovery from exercise-induced muscle damage (EIMD) is paramount in sports performance. Foam rolling (FR) has been suggested to improve acute performance; however, the ability to facilitate recovery from eccentric (ECC) exercise remains unclear.MethodsEleven males undertook 6 × 25 ECC knee extensions to induce muscular damage. Immediately, 24, 48, and 72 h post-training countermovement jump (CMJ), maximal voluntary isometric contraction (MVIC), pressure-pain threshold (PPT), knee flexion range of motion (ROM), and mid-thigh circumference (MTC) were assessed. Neurophysiological measures included voluntary activation (VA), peak twitch torque (PTT), time to peak twitch (PTTtime), and rate of twitch torque development (RTD). Participants then spent 15 min FR prior to each time point or control (CON). Repeated measures analysis of variance (ANOVA) and standardized effect sizes (Hedges’ g) ± 95% confidence intervals (95% CI) were used to compare FR and CON.ResultsCMJ was greater for FR compared to CON (P = 0.030) at 72 h (8.6%, P = 0.004) with moderate effects observed at 48 and 72 h (g = 0.54–0.66). PPT was greater with FR (P = 0.018) at 48 h only (23.7%, P = 0.013), with moderate to large effects noted at all-time points (g = 0.55–0.98). No significant differences were reported for MVIC (P = 0.777, -5.1 to 4.2%), ROM (P = 0.432, 1.6–3.5%), VA (P = 0.050, 3.6–26.2%), PTT (P = 0.302, -3.9 to 9.9%), PTTtime (P = 0.702, -24.4 to 23.5%), RTD (P = 0.864, -16.0 to -1.0%), or MTC (P = 0.409, -0.5 to -0.1%) between conditions.ConclusionFR appears to improve jump performance in the later stages of recovery following ECC exercise. This may be in part due to improved pain tolerance; however, mechanical and neurophysiological are not modulated with FR.

Increased knee loading in stair ambulation in patients dissatisfied with their total knee replacement

BackgroundTotal knee replacement patients have shown reductions in knee flexion range of motion, knee extensor moments, and gait speed during stair ascent and stair descent. However, it is unknown how patients dissatisfied with their total knee replacement differ from those who are satisfied during more difficult activities such as stair negotiation. Therefore, the purpose of this study was to compare knee biomechanics of patients who are dissatisfied with their joint replacement to those who are satisfied and healthy participants during stair negotiation. MethodsNine dissatisfied, fifteen satisfied patients and fifteen healthy participants participated, completing stair ascent and descent trials on an instrumented staircase. A 2 × 3 ANOVA was used to analyze biomechanical differences between groups and limbs during both activities. FindingsThe dissatisfied group showed reduced 2nd peak vertical GRF (P ≤ 0.0040) and loading-response knee extension moments (P ≤ 0.0041) in their operated limb compared to their non-operated limb and to satisfied and healthy groups during stair ascent. First peak vertical GRF (P < 0.0088) and both loading-response (P < 0.0117) and push-off abduction moments (P < 0.0028) showed reduced values in operated limbs compared to non-operated limbs for all groups. During stair descent, the dissatisfied group showed reduced loading-response and push-off knee extension moments (P ≤ 0.006) in their operated limb compared to their non-operated limb and the healthy group. The loading-response knee extension (P < 0.0379) and abduction moments (P ≤ 0.0048) were also reduced in the dissatisfied group compared to the satisfied group. InterpretationPatients who were dissatisfied showed asymmetrical loading of the knees in conjunction, which may have contributed to their dissatisfaction.

Predictors of pain intensity and Oswestry Disability Index in prolonged standing service workers with nonspecific chronic low back pain subclassified as active extension pattern

BackgroundBecause patients with nonspecific chronic low back pain (NSCLBP) are heterogeneous, subgrouping patients with NSCLBP might clarify the research findings. NSCLBP in the direction of extension movement, namely active extension pattern (AEP), is common during prolonged standing. ObjectivePredictors of pain intensity and dysfunction were determined in prolonged standing service workers (PSSWs) with NSCLBP subclassified as AEP in the motor impairment subgroup. MethodsVariables were measured using questionnaires including a visual analog scale (VAS), the Oswestry Disability Index (ODI), Borg Rating of Perceived Exertion (RPE) Scale, and Korean Occupational Stress Scale (KOSS). Postural assessment was performed by measuring pelvic anterior tilting angle (PATA). The smart KEMA measurement system was used to evaluate hip flexion, hip extension (HE), and knee flexion range of motion (ROM), as well as hip extensor strength, hip abductor strength (HArS), hip external rotator strength (HERrS), hip internal rotator strength, knee extensor strength, and knee flexor strength, and lumbopelvic stability (LS) in 78 PSSWs with NSCLBP subclassified as AEP. ResultsIn prediction models, HArS, LS, PATA, KOSS and HE ROM accounted for 40.1% of the variance in the VAS (p < 0.05); predictors of dysfunction included the HERrS and age, which accounted for 11.9% of the variance in the ODI (p < 0.05) in multiple regression models when using a stepwise selection procedure. ConclusionsThe present results indicate that HArS and HERrS, LS, PATA, KOSS, HE ROM and age should be considered for evaluating and predicting NSCLBP subclassified as AEP in PSSWs, and when designing interventions.

A Reliable Video-based ACL Injury Screening Tool for Female Team Sport Athletes.

This study aimed to develop a 2-dimensional (2D) video screening tool capable of predicting an athlete's peak 3-dimensional (3D) knee moments during unplanned sidestepping. 2D video-based kinematic measures were simultaneously captured with 3D peak knee moments for 30 female field hockey players (15 junior, 15 senior). Intra- and intertester repeatability of 2D kinematic measures was performed. Then, linear regression models were used to model 3D knee moments from 2D kinematic variables utilizing 80% of the sample (n=24). Regression equations were then validated on the remaining 20% of the sample (n=6). Angular 2D measures had good-excellent intra- (ICC=0.936-0.998) and intertester (ICC=0.662-0.949) reliability. Displacement measures had poor-excellent intra- (ICC=0.377-0.539) and inter-tester (ICC=0.219-0.869) reliability. Significant independent predictors of peak knee moments were dynamic knee valgus, knee flexion angle at foot strike, trunk flexion range of motion (ROM), trunk lateral flexion, hip abduction and knee flexion ROM (P<0.05). Regression equations generated from these models effectively predicted peak knee extension, valgus and internal rotation moments (i. e., were not different from measured values P>0.05, ES<0.4) in the 20% subsample. 2D video-based measurements of an athlete's full body kinematics during unplanned sidestepping provide a reliable, specific, sensitive and cost-effective means for screening female team sport athletes.