Lunge Exercise Research Articles

Does pain relate with activation of quadriceps and hamstrings muscles during strengthening exercise in people with knee osteoarthritis?

Muscle strengthening may be difficult to achieve in knee osteoarthritis (OA) due to pain. A large knee adduction moment (KAM), representing medial relative to lateral knee load, may also relate with pain during strengthening exercise. The objective of this study was to examine relationships between knee pain status and electromyography (EMG) amplitude of knee muscles during squat and lunge exercises. We also evaluated relationships between pain and KAM during these exercises. Forty-two women with symptomatic knee OA participated. Knee pain intensity and frequency were captured with two reliable and valid questionnaires. Motion analyses of squat and lunge exercises were completed. Total average EMG amplitude across five muscles of the lower limb and average KAM were calculated from the static portion of these exercises. Multiple regression analyses examined the relationships between pain and total average EMG amplitude; and pain and average KAM during squats and lunges. Pain improved the model for KAM from the trailing leg of a lunge. Pain did not improve any other model. Overall, pain may not be a useful indicator of EMG amplitude or KAM during exercise in knee OA.

Sagittal kinematics of mobile unicompartmental knee replacement in anterior cruciate ligament deficient knees

BackgroundThere is a greater risk of tibial component loosening when mobile unicompartmental knee replacement is performed in anterior cruciate ligament deficient knees. We previously reported on a cohort of anterior cruciate ligament deficient patients (n=46) who had undergone surgery, but no difference was found in implant survivorship at a mean 5-year follow-up. The purpose of this study was to examine the kinematic behaviour of a subcohort of these patients. MethodsThe kinematic behaviour of anterior cruciate deficient knees (n=16) after mobile unicompartmental knee replacement was compared to matched intact knees (n=16). Sagittal plane knee fluoroscopy was taken while patients performed step-up and forward lunge exercises. The patellar tendon angle, knee flexion angle and implant position was calculated for each video frame. FindingsThe patellar tendon angle was 5° lower in the deficient group, indicating greater anterior tibial translation compared to the intact group between 30 and 40° of flexion. Large variability, particularly from 40–60° of flexion, was observed in the bearing position of the deficient group, which may represent different coping mechanisms. The deficient group took 38% longer to perform the exercises. InterpretationKinematic differences were found between the deficient and intact knees after mobile unicompartmental knee replacement; but these kinematic changes do not seem to affect the medium-term clinical outcome. Whether these altered knee kinematics will have a clinical impact is as yet undetermined, but more long-term outcome data is required before mobile unicompartmental knee replacement can be recommended for an anterior cruciate ligament deficient patient.

Fluoroscopic Analysis of Tibial Translation in Anterior Cruciate Ligament Injured Knees With and Without Bracing During Forward Lunge.

Background:Despite several studies with different methods, the effect of functional knee braces on knee joint kinematics is not clear. Direct visualization of joint components through medical imaging modalities may provide the clinicians with more useful information.Objectives:In this study, for the first time in the literature, video fluoroscopy was used to investigate the effect of knee bracing on the sagittal plane kinematics of anterior cruciate ligament (ACL) injured patients.Patients and Methods:For twelve male unilateral ACL deficient subjects, the anterior tibial translation was measured during lunge exercise in non-braced and braced conditions. Fluoroscopic images were acquired from the subjects using a digital fluoroscopy system with a rate of 10 fps. The image of each frame was scaled using a calibration coin and analyzed in AutoCAD environment. The angle between the two lines, tangent to the posterior cortexes of the femoral and tibial shafts was measured as the flexion angle. For the fluoroscopic images associated with 0°, 15°, 30°, 45° and 60° knee flexion angles, the relative anterior-posterior configuration of the tibiofemoral joint was assessed by measuring the position of landmarks on the tibia and femur.Results:Results indicated that the overall anterior translations of the tibia during the eccentric (down) and concentric (up) phases of lunge exercise were 10.4 ± 1.7 mm and 9.0 ± 2.2 mm for non-braced, and 10.1 ± 3.4 mm and 7.4 ± 2.5 mm, for braced conditions, respectively. The difference of the tibial anterior-posterior translation behaviors of the braced and non-braced knees was not statistically significant.Conclusion:Fluoroscopic imaging provides an effective tool to measure the dynamic behavior of the knee joint in the sagittal plane and within the limitations of this study, the pure mechanical stabilizing effect of functional knee bracing is not sufficient to control the anterior tibial translation of the ACL deficient patients during lunge exercise.

Electromyographic analysis of anterior cruciate deficient knees with and without functional bracing during lunge exercise.

The use of functional knee braces for returning to sports or during demanding activities following anterior cruciate ligament rupture is common; yet despite being commonly prescribed, its mechanism of action remains unknown. To examine the effect of functional knee braces on mean muscle activity when performing lunge exercises. Pre-/post-test (within-subject research design). A total of 10 male participants with unilateral isolated anterior cruciate ligament deficiency participated. Electromyographic activities of six muscles around the knee were recorded during lunge exercises, with and without wearing a custom functional knee brace. The lunge cycle movement was subdivided into three phases: eccentric, isometric, and concentric. The quadriceps and hamstrings were no different in the braced and unbraced conditions. When braced, the mean amplitude of the medial gastrocnemius was significantly lower throughout the whole movement (p = 0.01) and during the concentric (p = 0.006) and eccentric (p = 0.028) phases, but not within the isometric phase. The lateral gastrocnemius was found to have lower mean amplitude in the isometric phase (p = 0.044). With its origin on the medial femoral condyle, perhaps reduced medial gastrocnemius activity may better guide knee rotation and assist the joint achieving a healthier kinematic pattern. Lower medial gastrocnemius activity may facilitate lower medial compartment contact pressure, for which greater loading is known to increase the risk of osteoarthritis in anterior cruciate ligament-deficient (ACLD) knees. However, further research is needed.

Training the hip: A progressive approach

In this article a progressive series of exercises to enhance motor control or movement competency of the hip are described. The training begins with control of center of mass during forward leaning by the muscles of the sole of the foot. This progresses to a novel lunge exercise emphasizing eccentric quadriceps control the knee. Then gluteal training is shown in a modern variation on Tai Chi along with a hip stability exercise during trunk rolling movements.

Nonuniform Changes in MRI Measurements of the Thigh Muscles After Two Hamstring Strengthening Exercises

Although many different hamstring strengthening exercises exist, the effect on site specific activation of these exercises on different muscles of the leg is unclear. This study investigated the effects of the eccentric leg curl (LC) and lunge (L) exercises on the biceps femoris long head (BFl), biceps femoris short head (BFs), semitendinosus (ST), semimembranosus (SM), and adductor magnus (AM). Each leg of 11 male professional soccer players was randomly assigned to an LC or L exercise protocol (3 sets of 6 repetitions). Functional magnetic resonance imaging (fMRI) of the subjects' thighs were performed before and 48 hours after the intervention. Fifteen axial scans of the thigh interspaced by a distance of 1/15 right femur length (Lf) were obtained. The fMRI data were analyzed for signal intensity changes. No significant changes were observed in absolute short tau inversion recovery values for the SM and BFs. Significant changes for the ST (∼21-45%) from sections 4 to 10, AM (∼2-13%) at section 4, and BFl (∼ -3 vs. 8%) at section 7 were noted. LC exercises load all the regions of the ST muscle. The L exercises load the proximal regions of the BFl and AM. These findings may have relevance when designing protocols for prevention and rehabilitation of hamstring injuries.

Effects of Various Foot Wedge Boards on Vastus Medialis Oblique and Vastus Lateralis Muscles during Lunge Exercise

Effects of Various Foot Wedge Boards on Vastus Medialis Oblique and Vastus Lateralis Muscles during Lunge Exercise

Bicruciate substituting total knee replacement: how effective are the added kinematic constraints in vivo?

The Journey bicruciate substituting (BCS) TKR was designed to restore normal knee kinematics. It has two cam-post mechanisms which substitute for the ACL and PCL. The aim of this study was to undertake a comprehensive study of the Journey BCS kinematics in vivo to assess the function of the cam-post mechanisms and their effect on functional kinematics and compared to the kinematics of a group of normal knees. The kinematics of 10 Journey BCS were assessed fluoroscopically during step-up and lunge exercises, and were compared to those of 20 normal knees. The fluoroscopic images were used to determine relative implant orientation using a 2D to 3D reconstruction method. The determined relative tibio-femoral orientations allowed for cam-post engagement and tibio-femoral contact points to be determined. Functional kinematics were assessed using the patella tendon angle (PTA) and the patella flexion angle (PFA) relationship with the knee flexion angle (KFA). The average maximum flexion achieved by the Journey was 124.7°. Both cam mechanisms engaged: The anterior cam during extension at 12.6° and the posterior cam in flexion at 45.4°. During flexion, the contacts points on the tibia moved posteriorly with no paradoxical anterior translation. The PTA/KFA relationships of the Journey implant group for both the step-up and lunge exercises were broadly similar in terms of trend to those established for the normal knee but the PTA between 10° KFA and 140° KFA were significantly (P < 0.05) lower than that for the normal knees. The PFA/KFA trend for both the implant and normal groups showed a linear relationship; however, the values of PFA were higher for the Journey compared to the normal. The Journey BCS showed no paradoxical anterior movement and sufficient posterior femoral roll back which corresponded with the engagement of the anterior and posterior cam-post mechanisms. Trends shown by the PTA/KFA and PFA/KFA kinematic profiles observed for the Journey group were more normal than those seen with other designs of TKR. However, despite being more close to normal than other implants, the Journey group showed a different kinematic profile to that of the normal knees, which is most likely due to the femur being too far posterior relative to the tibia. Case-control study, retrospective, comparative study, Level III.

In vivo sagittal plane kinematics of the FPV patellofemoral replacement

Isolated symptomatic patellofemoral osteoarthritis has been reported in 2% of men and 8% of women older than the age of 55years in the community. With the development of improved designs and surgical techniques, interest in the use of patellofemoral replacement has increased. The primary aim of the newer generation of patellofemoral replacement implant designs has been to more closely reproduce normal knee kinematics. This study compares the functional sagittal plane in vivo kinematics of a contemporary patellofemoral prosthesis, the FPV, with normal knee kinematics using the patella tendon angle and patella flexion angle relationships with the knee flexion angle. The in vivo kinematics for a group of 8 patients (15 knees) with patellofemoral replacement and 22 normal subjects was measured for both a step-up and a lunge exercise using an established fluoroscopic method. The patella tendon angle characteristics of the implanted knees were similar to those of the normal knees for the step-up exercise with a significant difference only observed at 50° knee flexion angle. For the lunge exercise, the patella tendon angle for the implanted knee was consistently lower than that measured for the normal knee. Overall the subjects had excellent clinical scores post-patellofemoral replacement showing a significant improvement from their pre-operative scores. The kinematics of the FPV implant was closer to normal than those of total knee implants; however, there were still differences from the normal knees. III.

12-weeks Of Whole Body Vibration With Resistance Exercise Is Osteogenic At The Spine

Evidence supports weight-bearing activity as a means to increase bone mineral density (BMD) and lower risk for osteoporosis. Whole body vibration (WBV) training is a novel technique that has been minimally explored for its potential to influence bone health. Of note is the lack of independent research explaining health outcomes of WBV training. PURPOSE: Our aim was to evaluate whether WBV with resistance exercise could increase BMD at the spine. METHODS: We recruited 24 men and women between the ages of 18-23; 10 volunteers (6 male and 4 female) performed WBV exercise training, 3 times per week, for 12 weeks, while the remaining 14 subjects (4 male and 10 female) served as controls. WBV training on the Vibraflex 550 (Orthometrix, Naples, FL), began with static standing and progressed to include squat, deadlift, lunge, rowing, and push-up exercises. Frequency (15-26 Hz) of vibration, duration, repetitions, and the number of exercises varied systematically over 12 weeks. BMD at the anterior-posterior (AP) and lateral spine was measured using dual-energy x-ray absorptiometry (DXA, Hologic, Waltham, MA) before and after the 12-week program. Serum bone-specific alkaline phosphatase (BSAP) was evaluated in a subsample of participants via enzyme-linked immunosorbant assay (Quidel, Santa Clara, CA). RESULTS: At baseline, groups were statistically similar in age, height, weight, body mass index, calcium intake, and kilocalorie consumption. BMD at the AP spine and lateral spine was also similar between groups at baseline. A two-tailed t-test revealed significant differences (p=0.013) in the change in BMD at the lateral spine between the control (-0.0149±0.010 g/cm2) and WBV group (0.0221±0.012 g/cm2) with a trend for differences at the AP spine (-0.0087±0.007 g/cm2 vs. 0.0089±0.007 g/cm2, p=0.089). A t-test comparing BSAP of the WBV (31.39±10.79 U/L) and control groups (22.63±4.74 U/L) suggest higher levels of formation markers for the trained individuals (p=0.086). CONCLUSION: In this 12-week intervention, the WBV group experienced a 2.2% increase in BMD at the lateral spine (p=0.013) while the control group decreased 1.7%. These preliminary results suggest that WBV with resistance exercise is a potential training method that can be used to increase BMD, and thereby lower future risk of osteoporosis.

Trunk And Lower Extremity Kinetics During Variations Of The Forward Lunge Exercise

The forward lunge (FL) is commonly used for rehabilitation, injury prevention, and improving athletic performance. While the FL is an effective functional exercise, it trains movement primarily in the sagittal plane and previous research has shown that the hip extensors have relatively low activation compared to the knee extensors. By altering the FL, it is possible to increase the activation of the sagittal plane hip extensors and the frontal plane hip abductors/adductors. PURPOSE: To observe the changes in the kinetics of the trunk and lower extremities due to variations of the FL. METHODS: Eleven healthy males participated in the study (age 25±3 yr, height 180±5 cm, mass 84±15 kg). Four types of lunges were completed with 2 hand-held dumbbell loads (13.6, 27.2 kg): FL, FL with trunk forward (FLTF), wide step lunge at 30° (WSL), and WSL with trunk forward (WSLTF). Each lunge was performed 3 times (24 total trials). Lunges were performed on 2 portable force platforms while 33 retroreflective markers were tracked. Joint moments were calculated at the knee, hip, and L5/S1 joints, then normalized to body mass (Nm/kg). Multivariate ANOVA was used to test for significant differences (p<0.05). RESULTS: WSL and WSLTF had higher hip adduction (0.89±0.26 vs. 0.32±0.23), knee varus (0.51±0.21 vs. 0.29±0.13) and knee valgus moments (0.48±0.10 vs. 0.28±0.18) than FL and FLTF. FL and FLTF had higher hip abduction moments (0.56±0.32 vs. 0.09±0.07) than WSL and WSLTF. FLTF and WSLTF had higher hip extension (2.85 ± 0.43 vs. 2.40 ± 0.33) and L5/S1 extension moments (1.96 ± 0.42 vs. 1.38 ± 0.38) than FL and WSL. Higher dumbbell load resulted in higher peak hip extension (2.85 ± 0.43 vs. 2.40 ± 0.33) and L5/S1 extension moments (1.83 ± 0.53 vs. 1.51 ± 0.40) than lower dumbbell load. CONCLUSION: Wide step lunges may strengthen hip adductor muscles, but increased knee varus and valgus moments may be harmful to the knee joint. Trunk forward lunges and doubling the dumbbell load increased hip and L5/S1 extension moments without increasing knee varus and valgus moments. Trunk forward lunges and increased dumbbell loads may strengthen hip extensors while sparing the knee joints, but may be harmful to the lower back. Changes in joint loading as a function of lunge technique should be considered when training and when rehabilitating knee, hip, and low back injuries.

Cruciate Ligament Forces between Short-Step and Long-Step Forward Lunge

The purpose of this study was to compare cruciate ligament forces between the forward lunge with a short step (forward lunge short) and the forward lunge with a long step (forward lunge long). Eighteen subjects used their 12-repetition maximum weight while performing the forward lunge short and long with and without a stride. EMG, force, and kinematic variables were input into a biomechanical model using optimization, and cruciate ligament forces were calculated as a function of knee angle. A two-factor repeated-measure ANOVA was used with a Bonferroni adjustment (P < 0.0025) to assess differences in cruciate forces between lunging techniques. Mean posterior cruciate ligament (PCL) forces (69-765 N range) were significantly greater (P < 0.001) in the forward lunge long compared with the forward lunge short between 0 degrees and 80 degrees knee flexion angles. Mean PCL forces (86-691 N range) were significantly greater (P < 0.001) without a stride compared with those with a stride between 0 degrees and 20 degrees knee flexion angles. Mean anterior cruciate ligament (ACL) forces were generated (0-50 N range between 0 degrees and 10 degrees knee flexion angles) only in the forward lunge short with stride. All lunge variations appear appropriate and safe during ACL rehabilitation because of minimal ACL loading. ACL loading occurred only in the forward lunge short with stride. Clinicians should be cautious in prescribing forward lunge exercises during early phases of PCL rehabilitation, especially at higher knee flexion angles and during the forward lunge long, which generated the highest PCL forces. Understanding how varying lunging techniques affect cruciate ligament loading may help clinicians prescribe lunging exercises in a safe manner during ACL and PCL rehabilitation.

The Effect of Closed-Kinetic Chain Exercises and Open-Kinetic Chain Exercise on the Muscle Activity of Vastus Medialis Oblique and Vastus Lateralis

Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal conditions of the lower limb. The muscle imbalance between the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles is one of the main factors leading to the development of PFPS. The disparity in research and the necessity to add to the existing literature base led to the development of this study. The aim of this study was to investigate the effect of 2 closed kinetic chain exercises and 1 open kinetic chain exercise on VMO and VL muscle activity. Twenty-two healthy asymptomatic individuals participated in this study. The surface electromyography (EMG) of VMO and VL was measured and used to calculate the VMO:VL ratio during 3 different quadriceps-strengthening exercises (a double leg squat with isometric hip adduction exercise, an open kinetic chain knee extension exercise, and a lunge exercise). The double leg squat with isometric hip adduction exercise was shown to produce a significantly greater VMO:VL ratio (1.14:1) than the other 2 exercises (p = 0.015 and p = 0.005). The open kinetic chain knee extension exercises produced significantly greater activation of VL than the lunge exercise (p = 0.001 and p = 0.036). The lunge exercise produced the VMO:VL ratio (1.18:1) closest to the idealized ratio of 1:1. Potential clinical recommendations can be made proposing the lunge exercise as a key tool in early rehabilitation when restoring preferential VMO:VL ratio is essential. The double leg squat with isometric hip adduction exercise would be useful in maintaining correct patella tracking and selectively strengthening VMO.

Cruciate ligament tensile forces during the forward and side lunge

Background Although weight bearing lunge exercises are frequently employed during anterior cruciate ligament and posterior cruciate ligament rehabilitation, cruciate ligament tensile forces are currently unknown while performing forward and side lunge exercises with and without a stride. Methods Eighteen subjects used their 12 repetition maximum weight while performing a forward lunge and side lunge with and without a stride. A motion analysis system and biomechanical model were used to estimate cruciate ligament forces during lunging as a function of 0–90° knee angles. Findings Comparing the forward lunge to the side lunge across stride variations, mean posterior cruciate ligament forces ranged between 205 and 765 N and were significantly greater ( P < 0.0025) in the forward lunge long at 40°, 50°, 60°, 70°, and 80° knee angles of the descent phase and at 80°, 70°, 60° knee angles of the ascent phase. There were no significant differences ( P < 0.0025) in mean posterior cruciate ligament forces between with and without stride differences across lunging variations. There were no anterior cruciate ligament forces quantified while performing forward and side lunge exercises. Interpretation Clinicians should be cautious in prescribing forward and side lunge exercises during early phases of posterior cruciate ligament rehabilitation due to relatively high posterior cruciate ligament forces that are generated, especially during the forward lunge at knee angles between 40° and 90° knee angles. Both the forward and side lunges appear appropriate during all phases of anterior cruciate ligament rehabilitation. Understanding how forward and side lunging affect cruciate ligament loading over varying knee angles may help clinicians better prescribe lunging exercises in a safe manner during anterior cruciate ligament and posterior cruciate ligament rehabilitation.

Muscle activation and length changes during two lunge exercises: implications for rehabilitation

Eccentric exercises are commonly used as a treatment for various muscle and tendon injuries. During complex motions such as the forward lunge, however, it is not always clear which muscles may be contracting eccentrically and at what time. Because this exercise is used during rehabilitation, the purpose of this investigation was to determine what type of contractions take place during two different types of forward lunge and assess the implications for rehabilitation. Five experienced athletes performed five cycles for each of the walking and jumping forward lunges. Motion analysis was used to calculate the shortening or elongation of each muscle based on the change of position of their origin and insertion points during the lunge. Electromyography of the lateral hamstrings, rectus femoris and lateral gastrocnemius was combined with the muscle length change data to determine when isometric, concentric and eccentric activations occur during the lunge. Eccentric contractions in both the quadriceps and gastrocnemius were observed during the lunge. No hamstring eccentric contractions were found; however, the hamstrings showed isometric contractions during the first part of the stance phase.

Using Squat Testing to Predict Training Loads for the Deadlift, Lunge, Step-Up, and Leg Extension Exercises

The purpose of this study was to determine whether there is a linear relationship between the squat and a variety of quadriceps resistance training exercises for the purpose of creating prediction equations for the determination of quadriceps exercise loads based on the squat load. Six-repetition maximums (RMs) of the squat, as well as four common resistance training exercises that activate the quadriceps including the deadlift, lunge, step-up, and leg extension, were determined for each subject. Subjects included 21 college students. Data were evaluated using linear regression analysis to predict quadriceps exercise loads from 6RM squat data and were cross-validated with the prediction of sum of squares statistic. Analysis of the data revealed that the squat is a significant predictor of loads for the dead lift (R2 = 0.81, standard error of the estimate [SEE] = 12.50 kg), lunge (R2 = 0.62, SEE = 12.57 kg), step-up (R2 = 0.71, SEE = 9.58 kg), and leg extension (R2=0.67, SEE = 10.26 kg) exercises. Based on the analysis of the data, the following 6RM prediction equations were devised for each exercise: (a) deadlift load = squat load (0.83) + 14.92 kg, (b) lunge load = squat load (0.52) + 14.82 kg, (c) step-up load = squat load (0.50) + 3.32 kg, and (d) leg extension load = squat load (0.48) + 9.58 kg. Results from testing core exercises such as the squat can provide useful data for the assignment of loads for other exercises.

Patellofemoral Joint Force and Stress Between a Short- and Long-Step Forward Lunge

Controlled laboratory biomechanics study using a repeated-measures, counterbalanced design. To compare patellofemoral joint force and stress between a short- and long-step forward lunge both with and without a stride. Although weight-bearing forward-lunge exercises are frequently employed during rehabilitation for individuals with patellofemoral joint syndrome, patellofemoral joint force and stress and how they change with variations of the lunge exercise are currently unknown. Eighteen subjects used their 12-repetition maximum weight while performing a short- and long-step forward lunge both with and without a stride. Electromyography, ground reaction force, and kinematic variables were put into a biomechanical optimization model, and patellofemoral joint force and stress were calculated as a function of knee angle. Visual observation of the data show that during the forward lunge, patellofemoral joint force and stress increased progressively as knee flexion increased, and decreased progressively as knee flexion decreased. Between 70 degrees and 90 degrees of knee flexion, patellofemoral joint force and stress were significantly greater when performing a forward lunge with a short step compared to a long step (P<.025). Between 10 degrees and 40 degrees of knee flexion, patellofemoral joint force and stress were significantly greater when performing a forward lunge with a stride compared to without a stride (P<.025). When the goal is to minimize patellofemoral joint force and stress during the forward lunge performed between 0 degrees to 90 degrees knee angles, it may be prudent to perform the lunge with a long step compared to a short step and without a stride compared to with a stride, because patellofemoral joint force and stress magnitudes were greater with a short step compared to a long step at higher knee flexion angles and were greater with a stride compared to without a stride at lower knee flexion angles.

Patellofemoral compressive force and stress during the forward and side lunges with and without a stride

Background Although weight bearing lunge exercises are frequently employed during patellofemoral rehabilitation, patellofemoral compressive force and stress are currently unknown for these exercises. Methods Eighteen subjects used their 12 repetition maximum weight while performing forward and side lunges with and without a stride. EMG, force platform, and kinematic variables were input into a biomechanical model, and patellofemoral compressive force and stress were calculated as a function of knee angle. Findings Patellofemoral force and stress progressively decreased as knee flexion increased and progressively increased as knee flexion decreased. Patellofemoral force and stress were greater in the side lunge compared to the forward lunge between 80° and 90° knee angles, and greater with a stride compared to without a stride between 10° and 50° knee angles. There were no significant interactions between lunge variations and stride variations. Interpretation A more functional knee flexion range between 0° and 50° may be appropriate during the early phases of patellofemoral rehabilitation due to lower patellofemoral compressive force and stress during this range compared to higher knee angles between 60° and 90°. Moreover, when the goal is to minimize patellofemoral compressive force and stress, it may be prudent to employ forward and side lunges without a stride compared to with a stride, especially at lower knee angles between 0° and 50°. Understanding differences in patellofemoral compressive force and stress among lunge variations may help clinicians prescribe safer and more effective exercise interventions.

Patellofemoral Compressive Force and Stress During the Forward and Side Lunge With and Without a Stride

PURPOSE: Because weight bearing lunge exercises are frequently employed during patellofemoral rehabilitation, the purpose was to determine patellofemoral compressive force and stress during forward and side lunge exercises. METHODS: Eighteen subjects used their 12 repetition maximum weight while performing forward and side lunges with and without a stride. EMG, force platform, and kinematic variables were input into a biomechanical model, and patellofemoral compressive force and stress were calculated as a function of knee flexion angles. RESULTS: Between 0-60° knee flexion angles patellofemoral compressive force and stress were greater in the forward lunge with stride compared to the side lunge with stride. Between 0-50° knee flexion angles patellofemoral compressive force and stress were significantly greater in the forward lunge with stride compared to the forward lunge without stride. Patellofemoral compressive force and stress increased progressively as knee flexion angles increased. CONCLUSIONS: More functional knee flexion angles between 0-50° may be appropriate during the early phases of patellofemoral rehabilitation due to lower patellofemoral compressive force and stress during this range compared to higher knee flexion angles between 60-90°. Moreover, when the goal is to minimize patellofemoral compressive force and stress, it may be prudent to employ the side lunge compared to the forward lunge, and the forward lunge without stride compared to the forward lunge with stride, especially in early phases of patellofemoral rehabilitation. Understanding differences in patellofemoral compressive force and stress among lunge variations help clinicians prescribe safer and more effective exercise interventions.

Influence of Shoes Increasing Dorsiflexion and Decreasing Metatarsus Flexion on Lower Limb Muscular Activity During Fitness Exercises, Walking, and Running

The aim of the present study was to compare electromyographic activity during fitness exercises, walking, and running among 3 different dorsiflexion shoes (+2 degrees , +4 degrees , and +10 degrees ) and standard shoes (-4 degrees ). The 3 different dorsiflexion shoes tested in this study have a curvature placed in the middle of the sole. This design was specially projected to decrease the metatarsus flexion. Electromyographic activity of 9 lower limb muscles was measured on 12 healthy female subjects during 5 fitness exercises (unload squat, side and front step, submaximal ballistic plantar flexion, and lunge exercise), and during running (10 km x h(-1)) and walking (4.5 km x h(-1)) on a treadmill. EMG signal was analyzed with the root mean square (RMS) and integrated EMG. All RMS data measured during these exercises were expressed as percentages of maximum voluntary isometric contraction. The results show that dorsiflexion affects muscle recruitment and reorganizes the motor pattern. The general tendency was that the tibialis anterior activity increased with dorsiflexion. However, an optimal dorsiflexion existed for various exercises. It is concluded that shoes with moderate dorsiflexion can activate lower limb muscles differently compared with both standard shoes and shoes with large dorsiflexion during submaximal exercises and locomotion.