scholarly journals Lower Extremity Biomechanics During a Drop-Vertical Jump and Muscle Strength in Women With Patellofemoral Pain

2020 ◽  
Vol 55 (6) ◽  
pp. 615-622
Author(s):  
Andrea Baellow ◽  
Neal R. Glaviano ◽  
Jay Hertel ◽  
Susan A. Saliba
Keyword(s):  
Lower Extremity ◽  
Knee Flexion ◽  
Vertical Jump ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Trunk Flexion ◽  
Healthy Group ◽  
Lower Extremity Biomechanics ◽  
Hip Internal Rotation ◽  
Kinematics And Kinetics

Context Patellofemoral pain (PFP) is one of the most prevalent knee conditions observed in women. Current research suggests that individuals with PFP have altered muscle activity, kinematics, and kinetics during functional tasks. However, few authors have examined differences in lower extremity biomechanics in this population during the drop-vertical jump (DVJ). Objective To determine how lower extremity electromyography, kinematics, and kinetics during a DVJ and lower extremity isometric strength differed between women with and those without PFP. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants Fifteen healthy women (age = 20.23 ± 1.39 years, height = 169.32 ± 5.38 cm, mass = 67.73 ± 9.57 kg) and 15 women with PFP (age = 22.33 ± 3.49 years, height = 166.42 ± 6.01 cm, mass = 65.67 ± 13.75 kg). Intervention(s) Three trials of a DVJ. Main Outcome Measure(s) Surface electromyography, kinematics, and kinetics were collected simultaneously during a DVJ. Lower extremity strength was measured isometrically. Independent-samples t tests were performed to assess group differences. Results Normalized muscle activity in the vastus medialis (healthy group = 120.84 ± 80.73, PFP group = 235.84 ± 152.29), gluteus maximus (healthy group = 43.81 ± 65.63, PFP group = 13.37 ± 13.55), and biceps femoris (healthy group = 36.68 ± 62.71, PFP group = 11.04 ± 8.9) during the landing phase of the DVJ differed between groups. Compared with healthy women, those with PFP completed the DVJ with greater hip internal-rotation moment (0.04 ± 0.28 N/kg versus 0.06 ± 0.14 N/kg, respectively) and had decreased knee-flexion excursion (76.76° ± 7.50° versus PFP = 74.14° ± 19.85°, respectively); they took less time to reach peak trunk flexion (0.19 ± 0.01 seconds versus 0.19 ± 0.02 seconds, respectively) and lateral trunk flexion (0.12 ± 0.07 seconds versus 0.11 ± 0.04 seconds, respectively). Conclusions During the DVJ, women with PFP had increased hip internal-rotation moment and decreased knee-flexion excursion with less time to peak trunk flexion and lateral flexion. Muscle activation was increased in the vastus medialis but decreased in the gluteus maximus and biceps femoris. This suggests that altered motor-unit recruitment in the hip and thigh may result in changes in biomechanics during a DVJ that are often associated with an increased risk of injury.

Lower-Extremity Biomechanics and Maintenance of Vertical-Jump Height During Prolonged Intermittent Exercise

2014 ◽  
Vol 23 (4) ◽  
pp. 319-329
Author(s):  
Randy J. Schmitz ◽  
John C. Cone ◽  
Timothy J. Copple ◽  
Robert A. Henson ◽  
Sandra J. Shultz
Keyword(s):  
Lower Extremity ◽  
Outcome Measures ◽  
Principal Components ◽  
Intermittent Exercise ◽  
Vertical Jump ◽  
The Body ◽  
Rating Of Perceived Exertion ◽  
Jump Height ◽  
Lower Extremity Biomechanics ◽  
Biomechanical Factors

Context:Potential biomechanical compensations allowing for maintenance of maximal explosive performance during prolonged intermittent exercise, with respect to the corresponding rise in injury rates during the later stages of exercise or competition, are relatively unknown.Objective:To identify lower-extremity countermovement-jump (CMJ) biomechanical factors using a principal-components approach and then examine how these factors changed during a 90-min intermittent-exercise protocol (IEP) while maintaining maximal jump height.Design:Mixed-model design.Setting:Laboratory.Participants:Fifty-nine intermittent-sport athletes (30 male, 29 female) participated in experimental and control conditions.Interventions:Before and after a dynamic warm-up and every 15 min during the 1st and 2nd halves of an individually prescribed 90-min IEP, participants were assessed on rating of perceived exertion, sprint/cut speed, and 3-dimensional CMJ biomechanics (experimental). On a separate day, the same measures were obtained every 15 min during 90 min of quiet rest (control).Main Outcome Measures:Univariate piecewise growth models analyzed progressive changes in CMJ performance and biomechanical factors extracted from a principal-components analysis of the individual biomechanical dependent variables.Results:While CMJ height was maintained during the 1st and 2nd halves, the body descended less and knee kinetic and energetic magnitudes decreased as the IEP progressed.Conclusions:The results indicate that vertical-jump performance is maintained along with progressive biomechanical changes commonly associated with decreased performance. A better understanding of lower-extremity biomechanics during explosive actions in response to IEP allows us to further develop and individualize performance training programs.

Muscle coordination in cycling: effect of surface incline and posture

1998 ◽  
Vol 85 (3) ◽  
pp. 927-934 ◽  
Author(s):  
Li Li ◽  
Graham E. Caldwell
Keyword(s):  
Lower Extremity ◽  
High Speed ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extensors ◽  
Emg Activity ◽  
Muscle Coordination

The purpose of the present study was to examine the neuromuscular modifications of cyclists to changes in grade and posture. Eight subjects were tested on a computerized ergometer under three conditions with the same work rate (250 W): pedaling on the level while seated, 8% uphill while seated, and 8% uphill while standing (ST). High-speed video was taken in conjunction with surface electromyography (EMG) of six lower extremity muscles. Results showed that rectus femoris, gluteus maximus (GM), and tibialis anterior had greater EMG magnitude in the ST condition. GM, rectus femoris, and the vastus lateralis demonstrated activity over a greater portion of the crank cycle in the ST condition. The muscle activities of gastrocnemius and biceps femoris did not exhibit profound differences among conditions. Overall, the change of cycling grade alone from 0 to 8% did not induce a significant change in neuromuscular coordination. However, the postural change from seated to ST pedaling at 8% uphill grade was accompanied by increased and/or prolonged muscle activity of hip and knee extensors. The observed EMG activity patterns were discussed with respect to lower extremity joint moments. Monoarticular extensor muscles (GM, vastus lateralis) demonstrated greater modifications in activity patterns with the change in posture compared with their biarticular counterparts. Furthermore, muscle coordination among antagonist pairs of mono- and biarticular muscles was altered in the ST condition; this finding provides support for the notion that muscles within these antagonist pairs have different functions.

scholarly journals The Kinematics and Kinetics Analysis of the Lower Extremity in the Landing Phase of a Stop-jump Task

2015 ◽  
Vol 9 (1) ◽  
pp. 103-107 ◽  
Author(s):  
L Yin ◽  
D Sun ◽  
Q.C Mei ◽  
Y.D Gu ◽  
J.S Baker ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Ground Reaction Force ◽  
Knee Flexion ◽  
Reaction Force ◽  
Flexion Angle ◽  
Contact Phase ◽  
Peak Knee ◽  
Significant Difference ◽  
The Impact ◽  
Kinematics And Kinetics

Large number of studies showed that landing with great impact forces may be a risk factor for knee injuries. The purpose of this study was to illustrate the different landing loads to lower extremity of both genders and examine the relationships among selected lower extremity kinematics and kinetics during the landing of a stop-jump task. A total of 35 male and 35 female healthy subjects were recruited in this study. Each subject executed five experiment actions. Lower extremity kinematics and kinetics were synchronously acquired. The comparison of lower extremity kinematics for different genders showed significant difference. The knee and hip maximum flexion angle, peak ground reaction force and peak knee extension moment have significantly decreased during the landing of the stop-jump task among the female subjects. The hip flexion angle at the initial foot contact phase showed significant correlation with peak ground reaction force during landing of the stop-jump task (r=-0.927, p<0.001). The knee flexion angle at the initial foot contact phase had significant correlation with peak ground reaction force and vertical ground reaction forces during landing of the stop-jump task (r=-0.908, p<0.001; r=0.812, P=0.002). A large hip and knee flexion angles at the initial foot contact with the ground did not necessarily reduce the impact force during landing, but active hip and knee flexion motions did. The hip and knee flexion motion of landing was an important technical factor that affects anterior cruciate ligament (ACL) loading during the landing of the stop-jump task.

scholarly journals Difference in vertical jumping abilities, endurance and quickness of regeneration lower extremity muscle groups after physical effort between CrossFit and climbing athletes

2017 ◽  
Vol 127 (4) ◽  
pp. 168-172
Author(s):  
Piotr Gawda ◽  
Michał Ginszt ◽  
Jakub Smołka ◽  
Michał Paćko ◽  
Maria Skublewska-Paszkowska ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Vertical Jump ◽  
Gluteus Maximus ◽  
Myoelectric Activity ◽  
High Intensity Training ◽  
Lower Extremity Muscle ◽  
Sport Climbing ◽  
Jump Test ◽  
Vertical Jumping ◽  
Significant Difference

Abstract Introduction. Productive sporting performance in various sports disciplines often heavily depends on jumping abilities as well as on lower limb muscles power and endurance of the athletes involved. Both CrossFit, a popular high-intensity training program and sport climbing require lower extremity muscular power and endurance. Aim. The aim of this study was to compare vertical jumping abilities, endurance and quickness of the regeneration in gastrocnemius lateralis (GL), vastus medialis (VMO) and gluteus maximus (GM) muscles in CrossFit athletes and sport climbers. Material and methods. The study comprised 20 male athletes aged 24.3±4.7, divided into two equal groups: training CrossFit (CF) and sport climbers (SC). Vertical jump test was recorded by Vicon® motion capture system and AMTI® biomechanics force platforms. The myoelectric activity of the GL, VMO and GM muscles was recorded by myon®. Results. Significant difference in height of vertical jump in CrossFit athletes and sport climbers was observed (SC: 125.43 cm, 120.92 cm; CF: 110.42 cm, 110.86 cm; p<0.05). The endurance of the GL muscles in athletes using CrossFit training is significantly higher in comparison to sport climbers. Athletes training CrossFit have a better ability to recover GL, GM and VMO muscles than sport climbers. Conclusions. Sport climbers have better results in vertical jump tests than the athletes doing CrossFit. The endurance of the GL muscles in athletes doing CrossFit is higher in comparison to sport climbers. Athletes doing CrossFit have also better ability to muscles recover than sport climbers.

scholarly journals EFFECTS OF TRADITIONAL STRENGTH TRAINING AND OLYMPIC WEIGHTLIFTING IN HANDBALL PLAYERS

2019 ◽  
Vol 25 (3) ◽  
pp. 230-234
Author(s):  
Bárbara Slovak ◽  
Leandro Carvalho ◽  
Fernando Rodrigues ◽  
Paulo Costa Amaral ◽  
Deborah Duarte Palma ◽  
...  
Keyword(s):  
Strength Training ◽  
Vastus Lateralis ◽  
Vertical Jump ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Level Of Evidence ◽  
Jump Performance ◽  
Plyometric Exercise ◽  
Regular Training

ABSTRACT Introduction Olympic weightlifting has been adopted as an alternative to plyometric exercise. However, the effects of these exercises in young handball athletes is not known. Objective To compare the effect of Olympic weightlifting training with traditional strength training on jumping, squatting and acceleration performance in young handball athletes. Ten female handball athletes were evaluated. After six weeks of regular training, the athletes underwent eight weeks of training specifically designed for the survey, with equivalence of the total volume of training and differences in the means used. The evaluations were performed after six weeks of regular training (Baseline), after four weeks of traditional strength training and after four weeks of Olympic weightlifting. Vertical Jumps with and without movement of the arms, acceleration of 10 m, 20 m and 30 m, and 1RM in squatting were quantified. Results Increases (p<0.05) were observed in accelerations and squatting in the Olympic weightlifting and in squatting in the traditional strength training. Differences in coordination, time to activation of the gastrocnemius, vastus lateralis, rectus femoris, biceps femoris and gluteus maximus, peak force and power and rate of force development between the jumps and exercises used in the training are hypotheses to be considered for the different responses adaptations found in the jumps. Conclusion The Olympic weightlifting training resulted in an increase in accelerations and strength, but not in vertical jump performance in young handball athletes. Level of Evidence I; Prognostic Studies - Investigation of the Effect of a Patient Characteristic on Disease Outcome.

scholarly journals Changes in Lower Extremity Biomechanics Due to a Short-Term Fatigue Protocol

2013 ◽  
Vol 48 (3) ◽  
pp. 306-313 ◽  
Author(s):  
Nelson Cortes ◽  
Eric Greska ◽  
Roger Kollock ◽  
Jatin Ambegaonkar ◽  
James A. Onate
Keyword(s):  
Anterior Cruciate Ligament ◽  
Lower Extremity ◽  
Knee Flexion ◽  
Cruciate Ligament ◽  
Ligament Injury ◽  
Initial Contact ◽  
Fatigue Protocol ◽  
Lower Extremity Biomechanics ◽  
Anterior Cruciate ◽  
Hip Flexion

Context: Noncontact anterior cruciate ligament injury has been reported to occur during the later stages of a game when fatigue is most likely present. Few researchers have focused on progressive changes in lower extremity biomechanics that occur throughout fatiguing. Objective: To evaluate the effects of a sequential fatigue protocol on lower extremity biomechanics during a sidestep-cutting task (SS). Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Eighteen uninjured female collegiate soccer players (age = 19.2 ± 0.9 years, height = 1.66 ± 0.5 m, mass = 61.6 ± 5.1 kg) volunteered. Intervention(s): The independent variable was fatigue level, with 3 levels (prefatigue, 50% fatigue, and 100% fatigue). Using 3-dimensional motion capture, we assessed lower extremity biomechanics during the SS. Participants alternated between a fatigue protocol that solicited different muscle groups and mimicked actual sport situations and unanticipated SS trials. The process was repeated until fatigue was attained. Main Outcome Measure(s): Dependent variables were hip- and knee-flexion and abduction angles and internal moments measured at initial contact and peak stance and defined as measures obtained between 0% and 50% of stance phase. Results: Knee-flexion angle decreased from prefatigue (−17° ± 5°) to 50% fatigue (−16° ± 6°) and to 100% fatigue (−14° ± 4°) (F2,34 = 5.112, P = .004). Knee flexion at peak stance increased from prefatigue (−52.9° ± 5.6°) to 50% fatigue (−56.1° ± 7.2°) but decreased from 50% to 100% fatigue (−50.5° ± 7.1°) (F2,34 = 8.282, P = 001). Knee-adduction moment at peak stance increased from prefatigue (0.49 ± 0.23 Nm/kgm) to 50% fatigue (0.55 ± 0.25 Nm/kgm) but decreased from 50% to 100% fatigue (0.37 ± 0.24) (F2,34 = 3.755, P = 03). Hip-flexion angle increased from prefatigue (45.4° ± 10.9°) to 50% fatigue (46.2° ± 11.2°) but decreased from 50% to 100% fatigue (40.9° ± 11.3°) (F2,34 = 6.542, P = .004). Hip flexion at peak stance increased from prefatigue (49.8° ± 9.9°) to 50% fatigue (52.9° ± 12.1°) but decreased from 50% to 100% fatigue (46.3° ± 12.9°) (F2,34 = 8.639, P = 001). Hip-abduction angle at initial contact decreased from prefatigue (−13.8° ± 6.6°) to 50% fatigue (−9.1° ± 6.5°) and to 100% fatigue (−7.8° ± 6.5°) (F2,34 = 11.228, P &lt; .001). Hip-adduction moment decreased from prefatigue (0.14 ± 0.13 Nm/kgm) to 50% fatigue (0.08 ± 0.13 Nm/kgm) and to 100% fatigue (0.06 ± 0.05 Nm/kg) (F2,34 = 5.767, P = .007). Conclusions: The detrimental effects of fatigue on sagittal and frontal mechanics of the hip and knee were visible at 50% of the participants' maximal fatigue and became more marked at 100% fatigue. Anterior cruciate ligament injury-prevention programs should emphasize feedback on proper mechanics throughout an entire practice and not only at the beginning of practice.

scholarly journals Comparison of Lower Extremity Kinematics and Hip Muscle Activation During Rehabilitation Tasks Between Sexes

2010 ◽  
Vol 45 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Maureen K. Dwyer ◽  
Samantha N. Boudreau ◽  
Carl G. Mattacola ◽  
Timothy L. Uhl ◽  
Christian Lattermann
Keyword(s):  
Sex Differences ◽  
Lower Extremity ◽  
Knee Flexion ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Kinetic Chain ◽  
Closed Kinetic Chain ◽  
Hip Flexion ◽  
Rehabilitation Exercises

Abstract Context: Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises. Objective: To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises. Design: Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise). Setting: Research laboratory. Patients or Other Participants: Participants included 21 women (age  =  23 ± 5.8 years, height  =  167.6 ± 5.1 cm, mass  =  63.7 ± 5.9 kg) and 21 men (age  =  23 ± 4.0 years, height  =  181.4 ± 7.4 cm, mass  =  85.6 ± 16.5 kg). Intervention(s): In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises. Main Outcome Measure(s): We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise. Results: Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men. Conclusions: Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.

scholarly journals A Preliminary Multifactorial Approach Describing the Relationships Among Lower Extremity Alignment, Hip Muscle Activation, and Lower Extremity Joint Excursion

2011 ◽  
Vol 46 (3) ◽  
pp. 246-256 ◽  
Author(s):  
Anh-Dung Nguyen ◽  
Sandra J. Shultz ◽  
Randy J. Schmitz ◽  
Richard M. Luecht ◽  
David H. Perrin
Keyword(s):  
Lower Extremity ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Femoral Anteversion ◽  
Navicular Drop ◽  
Hip Muscle ◽  
Single Leg Squat ◽  
Multifactorial Approach ◽  
Hip Internal Rotation

Context: Multiple factors have been suggested to increase the risk of faulty dynamic alignments that predict noncontact anterior cruciate ligament injury. Few researchers have examined this relationship using an integrated, multifactorial approach. Objective: To describe the relationship among static lower extremity alignment (LEA), hip muscle activation, and hip and knee motion during a single-leg squat. Design: Descriptive laboratory study. Setting: Research laboratory. Patients or Other Participants: Thirty men (age = 23.9 ± 3.6 years, height = 178.5 ± 9.9 cm, mass = 82.0 ± 14.1 kg) and 30 women (age = 22.2 ± 2.6 years, height = 162.4 ± 6.3 cm, mass = 60.3 ± 8.1 kg). Main Outcome Measure(s): Pelvic angle, femoral anteversion, quadriceps angle, tibiofemoral angle, and genu recurvatum were measured to the nearest degree; navicular drop was measured to the nearest millimeter. The average root mean square amplitude of the gluteus medius and maximus muscles was assessed during the single-leg squat and normalized to the peak root mean square value during maximal contractions for each muscle. Kinematic data of hip and knee were also assessed during the single-leg squat. Structural equation modeling was used to describe the relationships among static LEA, hip muscle activation, and joint kinematics, while also accounting for an individual's sex and hip strength. Results: Smaller pelvic angle and greater femoral anteversion, tibiofemoral angle, and navicular drop predicted greater hip internal-rotation excursion and knee external-rotation excursion. Decreased gluteus maximus activation predicted greater hip internal-rotation excursion but decreased knee valgus excursion. No LEA characteristic predicted gluteus medius or gluteus maximus muscle activation during the single-leg squat. Conclusions: Static LEA, characterized by a more internally rotated hip and valgus knee alignment and less gluteus maximus activation, was related to commonly observed components of functional valgus collapse during the single-leg squat. This exploratory analysis suggests that LEA does not influence hip muscle activation in controlling joint motion during a single-leg squat.

Reliability of Using a Handheld Tablet and Application to Measure Lower-Extremity Alignment Angles

2015 ◽  
Vol 24 (4) ◽  
Author(s):  
Deborah L. King ◽  
Barbara C. Belyea
Keyword(s):  
At Risk ◽  
Lower Extremity ◽  
Knee Flexion ◽  
Interrater Reliability ◽  
Knee Injury ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Initial Contact ◽  
Experience Level ◽  
Lower Extremity Injuries

Context: Landing kinematics have been identified as a risk factor for knee injury. Detecting atypical kinematics in clinical settings is important for identifying individuals at risk for these injuries. Objective: To determine the reliability of a handheld tablet and application (app) for measuring lower-extremity kinematics during drop vertical-jump landings. Design: Measurement reliability. Setting: Laboratory. Participants: 23 healthy young adults with no lower-extremity injuries and no contraindications for jumping and landing. Intervention: Subjects performed 6 drop vertical jumps that were captured with an iPad2 and analyzed with a KinesioCapture app by 2 novice and 2 experienced raters. Three trials each were captured in the frontal and sagittal planes. Main Outcome Measures: Frontal-plane projection angles, knee flexion, and hip flexion at initial contact and maximum knee flexion were measured. ICC and SEM were calculated to determine intertrial and interrater reliability. One-way ANOVAs were used to examine differences between the measured angles of the raters. Results: Average intertrial reliability ranged from .71 to .98 for novice raters and .77 to .99 for experienced raters. SEMs were 2.3-4.3° for novice raters and 1.6-3.9° for experienced raters. Interrater ICC2,1 was .39-.98 for the novice raters and .69-.93 for the experienced raters. SEMs were smallest with the experienced raters, all less than 1.5°. Conclusion: A handheld tablet and app is promising for evaluating landing kinematics and identifying individuals at risk for knee injury in a clinical setting. Intertrial reliability is good to excellent when using average trial measures. Interrater reliability is fair to excellent depending on experience level. Multiple trials should be assessed by a single rater when assessing lower-extremity mechanics with a handheld tablet and app, and results may vary with experience level or training.

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