Understanding Hip Labrum Tears

The hip labrum is a specialized fibrocartilaginous structure that forms a complete ring around the acetabulum, the socket portion of the ball-and-socket hip joint. This triangular or wedge-shaped tissue serves critical biomechanical functions: it deepens the socket by approximately 20 percent, creates a suction seal that generates negative intra-articular pressure for joint stability, distributes synovial fluid for cartilage nutrition, and provides proprioceptive feedback about joint position. When the labrum is intact, the femoral head remains centered within the acetabulum during dynamic movement, and loads are transferred evenly across the articular surfaces. A labral tear disrupts these mechanisms, leading to instability, abnormal joint mechanics, and accelerated cartilage wear.

Labral tears in athletes present along a spectrum from partial-thickness fraying to full-thickness detachments. The tear location is clinically significant: anterosuperior tears are most common in athletes with femoroacetabular impingement (FAI), while posterior tears often occur from traumatic posterior dislocation or subluxation. The etiology divides broadly into two categories. Acute tears result from a single traumatic event such as a fall onto the hip, a sudden pivoting motion, or a hip dislocation during a collision sport. Chronic or degenerative tears develop from repetitive microtrauma—the cumulative effect of thousands of movements that place excessive shear or compressive forces on the labrum over months or years. In high-level athletes, repetitive microtrauma from sport-specific mechanics is the predominant mechanism.

The clinical presentation of a labral tear can mimic other hip pathologies, making diagnosis challenging without proper imaging. Athletes typically report deep groin pain that may radiate to the buttock or lateral thigh. Mechanical symptoms such as catching, locking, or a clicking sensation are common, along with a subjective feeling of instability or giving way. Range of motion is often restricted, particularly in internal rotation and flexion, and the athlete may experience pain during specific movements like squatting, pivoting, or rising from a seated position. The FABER test (flexion, abduction, external rotation) and the FADIR test (flexion, adduction, internal rotation) are provocative maneuvers that reproduce pain when the labrum is compromised. Definitive diagnosis typically requires magnetic resonance arthrography, where contrast injected into the joint enhances visualization of labral pathology, or direct visualization during hip arthroscopy.

The Role of Biomechanics in Injury Prevention

Biomechanics is the study of the mechanical laws governing human movement, including the forces acting on the body and the body's responses to those forces. In the context of sports injury prevention, biomechanical analysis identifies how movement patterns either protect or compromise joint structures. The hip joint is particularly vulnerable to biomechanical dysfunction because it must simultaneously provide mobility for athletic performance and stability for load transmission. When movement mechanics are optimal, forces from ground reaction and muscle activation are distributed evenly across the femoral head, labrum, and acetabular cartilage. When mechanics break down, abnormal stress concentrations develop, and the labrum becomes a primary load-bearing structure rather than a stabilizing seal.

Several biomechanical principles are directly relevant to labral health. First, joint centration refers to the maintenance of the femoral head within the acetabulum during movement. Proper centration ensures that contact pressures are distributed across the broadest possible surface area, minimizing focal stress on the labrum. Second, the concept of force closure describes how dynamic muscle activity compresses and stabilizes the joint. The hip is inherently stable due to its bony geometry, but muscle activation patterns dramatically influence how forces are transmitted across the joint. Third, the timing and sequence of muscle recruitment determines whether movement is smooth and coordinated or jerky and poorly controlled. Athletes who demonstrate delayed activation of the gluteal muscles during landing or cutting tasks place the labrum at increased risk because the passive stabilizers must compensate for inadequate dynamic control.

Research has identified specific movement patterns that predictably increase labral loading. Excessive femoral internal rotation during weight-bearing activities drives the femoral head against the anterosuperior labrum, producing shear stress that can initiate tearing. This pattern is commonly observed in athletes who demonstrate weak hip external rotators and abductors, as these muscles normally control femoral rotation during stance phase. Similarly, a Trendelenburg pattern—where the pelvis drops on the unsupported side during single-leg stance—indicates inadequate hip abductor function and shifts the center of rotation laterally, increasing the adduction moment at the hip and compressing the labrum against the acetabular rim. Anterior pelvic tilt, often resulting from tight hip flexors and weak abdominals, reduces the available clearance between the femoral neck and the acetabular rim, creating impingement that can pinch the labrum during hip flexion and internal rotation.

Common Biomechanical Deficits in Athletes

Clinical observation and motion analysis research have identified a set of recurring movement faults that predispose athletes to labral pathology. These deficits are not random but reflect predictable patterns of muscle imbalance, joint restriction, and neuromuscular control errors that can be systematically assessed and corrected.

  • Excessive and uncontrolled hip internal rotation – This deficit is prevalent in runners, dancers, and soccer players. During the stance phase of gait or during single-leg support in sport, the femur rotates internally beyond normal limits, driving the femoral head toward the labrum. The primary contributors are weak external rotators (piriformis, gemelli, obturators) and overactive or tight internal rotators (gluteus medius anterior fibers, adductors).
  • Pelvic instability during single-leg stance – A Trendelenburg sign or lateral pelvic drop indicates that the gluteus medius on the stance leg is unable to stabilize the pelvis. This lateral tilt shifts the hip joint into relative adduction, narrowing the joint space on the superior aspect and compressing the labrum. This pattern is common in runners, basketball players, and anyone performing single-leg landing or cutting tasks.
  • Muscle imbalances across the hip joint – The hip is surrounded by muscle groups that must work in coordinated opposition. When the adductors and hip flexors are tight and overactive while the abductors, extensors, and external rotators are weak and inhibited, the femoral head is pulled into a position of adduction and internal rotation that stresses the labrum. This imbalance is often measured through isokinetic strength testing and manual muscle testing.
  • Poor landing mechanics – Athletes who land from a jump with an upright trunk, limited hip and knee flexion, and a narrow base of support transmit impact forces directly through the hip joint with minimal muscular attenuation. The labrum absorbs a disproportionate share of this load, particularly if the femur is adducted and internally rotated at initial contact. Proper landing technique involves deep hip and knee flexion, a wider stance, and controlled knee alignment over the foot.
  • Inefficient cutting and change-of-direction technique – During a lateral cut or sidestep maneuver, the athlete must decelerate the body's momentum and redirect it in a new direction. If the trunk is too upright and the cutting leg remains relatively straight, the hip must absorb rotational forces without the benefit of muscular eccentric control. This places high shear stress on the labrum, particularly in the anterosuperior quadrant.
  • Limited hip range of motion – Restricted hip mobility, particularly in extension and external rotation, forces compensatory motion at the lumbar spine and pelvis. When the hip cannot achieve the required range for a given movement, the athlete adopts altered mechanics that increase labral loading. For example, a pitcher with limited hip external rotation may compensate by increasing anterior pelvic tilt and lumbar extension, altering the position of the acetabulum relative to the femur.

How Poor Biomechanics Lead to Labral Tears

The pathomechanics of labral tearing can be understood through the lens of tissue stress and cumulative load. The labrum is composed of dense fibrocartilage with a limited blood supply, making it vulnerable to repetitive microtrauma and slow to heal once damaged. When biomechanics are faulty, the labrum experiences stress beyond its physiological tolerance, and over time, structural failure occurs.

Consider a basketball player performing a layup and landing on one leg. If the player lands with the hip in a position of adduction and internal rotation—a common pattern when fatigued—the femoral head translates anteriorly and superiorly within the acetabulum. The labrum is compressed between the femoral head and the acetabular rim, and if the landing force is high enough, the labrum can tear at its attachment site. With repeated landings over a game or season, microdamage accumulates, and a partial-thickness tear can progress to a full-thickness detachment. The Clinical Journal of Sport Medicine has published evidence that athletes with weak hip abductors and external rotators demonstrate significantly greater hip adduction and internal rotation angles during landing compared to athletes with normal strength profiles, directly linking muscle function to injury risk.

In another common scenario, a soccer player performing a repeated kicking motion may develop anterior hip pain from impingement. During the follow-through phase of a powerful kick, the hip moves into extension with external rotation. If the athlete has a cam-type FAI—a bony bump on the femoral head-neck junction—the femoral neck impacts the anterosuperior labrum, causing compression and shear. Over hundreds of kicks per week, this repetitive impingement leads to labral chondral separation and full-thickness tearing. Similarly, a ballet dancer repeatedly achieving extreme hip turnout may develop posterior labral tears from the combined forces of deep flexion and external rotation. Research in the Journal of Biomechanics has demonstrated that dancers with poor lumbopelvic control show significantly greater anterior pelvic tilt during arabesque and grand plié, positions that narrow the femoroacetabular clearance and increase labral contact pressure.

Strategies for Improving Biomechanics

Preventing labral tears through biomechanical optimization requires a systematic approach that includes assessment, corrective exercise, neuromuscular retraining, and ongoing monitoring. The goal is to restore optimal joint centration, dynamic stability, and coordinated muscle activation during sport-specific tasks. Prevention programs are most effective when implemented before the onset of symptoms, but they also play a critical role in rehabilitation after injury or surgery to prevent recurrence.

Assessment Tools

A comprehensive biomechanical assessment identifies the specific deficits that place an athlete at risk. Multiple tools are available, ranging from simple observation to sophisticated technology, and the selection depends on the athlete's level, the resources available, and the clinical context.

  • Visual gait and movement analysis – A trained eye can identify many common faults during walking, running, squatting, landing, and cutting. Key observations include the position of the pelvis (level vs. tilted), the tracking of the knees relative to the feet, the depth of hip flexion during landing, and the symmetry of movement between sides. Slow-motion video recording enhances visual analysis and provides objective evidence for feedback.
  • Functional Movement Screen (FMS) – This standardized screening tool assesses seven fundamental movement patterns, including the deep squat, hurdle step, and active straight-leg raise. The FMS identifies asymmetries, mobility restrictions, and stability deficits that may predispose to injury. A composite score below 14 out of 21 has been associated with increased injury risk in athletic populations.
  • Selective Functional Movement Assessment (SFMA) – For athletes already experiencing symptoms, the SFMA provides a more detailed evaluation of movement patterns to differentiate between mobility and stability problems. This assessment is particularly useful for identifying the root cause of labral symptoms, such as whether the primary driver is a restriction in hip extension or a lack of core stability.
  • Instrumented motion capture – Three-dimensional motion analysis using infrared cameras and reflective markers provides precise, quantitative data on joint angles, angular velocities, and moments. This technology is the gold standard for research and is increasingly available in elite sports settings. For example, motion capture can measure the exact angle of femoral internal rotation during a cutting maneuver and quantify how that changes after a training intervention.
  • Isokinetic strength testing – Using a dynamometer, clinicians can measure peak torque, total work, and power for hip flexion, extension, abduction, adduction, and rotation. Strength ratios, such as the ratio of external rotation to internal rotation strength, provide targets for corrective training. A ratio of less than 0.75 for external rotation relative to internal rotation has been suggested as a risk factor for hip pathology.
  • Electromyography (EMG) – Surface or fine-wire EMG measures muscle activation timing and amplitude. This assessment can reveal delayed onset of stabilizing muscles, such as the gluteus medius, during functional tasks. Athletes who demonstrate late or reduced gluteal activation during landing are candidates for neuromuscular retraining.

Key Interventions for Optimal Hip Mechanics

Once biomechanical deficits are identified, targeted interventions can address the underlying causes. The most effective programs combine strengthening, mobility, neuromuscular training, and coaching in a progressive, sport-specific framework.

Strengthening the Hip and Core

Strengthening programs should target the muscles that control femoral and pelvic position. The gluteus medius is a primary target because it abducts and externally rotates the femur, preventing the adduction and internal rotation patterns that stress the labrum. Exercises such as side-lying hip abduction, clamshells with a resistance band, lateral band walks, and single-leg bridges activate the gluteus medius effectively. The gluteus maximus, the primary hip extensor and a powerful external rotator, is trained through exercises like hip thrusts, deadlifts, Romanian deadlifts, and single-leg squats. Deep external rotators—the piriformis, gemelli, and obturators—are addressed through exercises that emphasize external rotation at 90 degrees of hip flexion, such as the seated band external rotation or the 90-90 hip lift.

Core strengthening is equally important because the core connects the upper and lower extremities and provides a stable platform for hip function. The transversus abdominis, multifidus, pelvic floor, and diaphragm form a deep stabilization system that must activate before limb movement. Exercises such as dead bugs, side planks, bird dogs, and Pallof presses train this anticipatory core activation. A study in the Journal of Orthopaedic & Sports Physical Therapy demonstrated that a six-week core and hip strengthening program significantly reduced hip adduction angles during single-leg squatting and landing tasks in collegiate athletes, suggesting that improved lumbopelvic control directly enhances hip biomechanics.

Single-leg exercises are particularly valuable because sport involves predominantly single-leg stance and propulsion. Step-ups, Bulgarian split squats, single-leg Romanian deadlifts, and single-leg squats train the hip stabilizers to maintain joint centration under load. The focus should be on quality of movement rather than load: the athlete must maintain a level pelvis, controlled knee alignment, and an upright trunk throughout the movement. Progression is achieved by adding load, increasing speed, or introducing unstable surfaces only after perfect technique is established.

Flexibility and Mobility Work

Joint mobility and muscle flexibility are prerequisites for normal biomechanics. Restrictions in the hip capsule or the muscles surrounding the hip force compensatory patterns that increase labral stress. A comprehensive mobility program addresses the specific restrictions that are common in athletes.

Hip flexor tightness is almost universal in athletes who spend significant time in seated positions or in sports that emphasize hip flexion, such as cycling and running. The iliopsoas and rectus femoris become shortened and restrict hip extension, pulling the pelvis into anterior tilt. A half-kneeling hip flexor stretch with posterior pelvic tilt, performed daily, can restore extension range. The Thomas test is used to assess hip flexor length and monitor progress.

Adductor tightness contributes to excessive femoral internal rotation and limits the ability to maintain a neutral hip position during single-leg stance. Adductor stretches in a kneeling lunge position, along with foam rolling and active release techniques, can improve flexibility. However, caution is warranted because overly aggressive stretching of the adductors can destabilize the hip in some individuals. The goal is to achieve normal, symmetrical adductor length rather than maximal flexibility.

Hip capsule mobility is sometimes overlooked but is critical for the end-range positions that athletes encounter. A tight posterior capsule can limit internal rotation and force compensation through the lumbar spine. Self-mobilization techniques, such as the posterior capsule distraction using a belt or the hip flexor capsule mobilization, can maintain joint play. A physical therapist or athletic trainer can perform joint mobilizations to address specific capsular restrictions identified during assessment.

Dynamic warm-up routines that combine mobility, activation, and movement preparation are more effective than static stretching alone for preparing the hip for sport. A typical warm-up might include leg swings, walking lunges with rotation, glute bridges, clamshells, and controlled squats. This approach increases tissue temperature, activates the neuromuscular system, and rehearses sport-specific movement patterns before practice or competition.

Neuromuscular Training and Motor Control

Retraining movement patterns requires the athlete to consciously practice correct mechanics until they become automatic. This process, known as motor learning, relies on feedback, repetition, and progressive challenge. The athlete must first understand what correct movement looks and feels like, then practice it repeatedly in controlled settings before applying it in sport-specific and finally competitive environments.

External focus of attention has been shown to enhance motor learning more effectively than internal focus. Instead of telling the athlete to "externally rotate your femur" (internal focus), cues such as "spread the floor with your feet" or "drive your knees out" (external focus) produce better movement patterns. Visual feedback is especially powerful: when athletes see themselves on video performing a squat or landing with poor mechanics, they can compare their movement to a model and make corrections in real time. Video feedback tools, including slow-motion analysis apps, make this accessible at all levels of sport.

Plyometric training that emphasizes proper landing mechanics is a cornerstone of labral injury prevention. Athletes should progress through a sequence: first, learn the correct landing position in place (hips and knees bent, feet shoulder-width apart, weight on midfoot, trunk upright). Then, practice landing from small jumps, gradually increasing height and distance. Finally, incorporate landings with directional changes. Throughout this progression, the coach or therapist provides feedback on hip position, pelvic stability, and knee alignment. The goal is to ingrain a landing pattern that maintains the hip in a safe, centered position even under fatigue.

Agility and change-of-direction training must also address the cutting technique. Athletes who cut with an upright trunk and a narrow base are at high risk for labral injury. Correct cutting technique involves lowering the center of gravity by flexing the hips and knees, widening the base of support, and directing the trunk toward the new direction of travel before the foot plants. This position allows the hip to absorb and redirect forces through the muscles rather than through passive structures. Cues such as "load the hip," "stay low," and "push off through the outside leg" help athletes achieve this position.

Video Analysis and Coaching

Video analysis bridges the gap between subjective observation and objective feedback. With affordable high-speed cameras and analysis software, coaches and clinicians can capture an athlete's movement during practice and competition, then review it frame by frame to identify biomechanical faults. The key is to compare the athlete's movement to a biomechanical model of optimal technique for their sport and position.

For example, a baseball pitcher's delivery can be analyzed for hip and pelvic position during the stride and follow-through. Excessive hip internal rotation during the follow-through increases stress on the labrum and is associated with FAI. The coach can adjust the pitcher's stance, stride length, or trunk position to reduce this rotational stress. Similarly, a golfer's swing can be analyzed for pelvic rotation and hip position during the downswing and follow-through. The National Athletic Trainers' Association provides guidelines for integrating video analysis into injury prevention programs across multiple sports.

Regular video sessions, conducted every four to six weeks during the season, allow the athlete and coach to track progress and make adjustments as needed. This longitudinal approach is more effective than a one-time assessment because movement patterns can deteriorate with fatigue, accumulated training load, or minor injuries. By catching these breakdowns early, the athlete can be redirected toward correct mechanics before tissue damage occurs.

Sport-Specific Considerations

While the fundamental principles of hip biomechanics apply across all sports, each sport places unique demands on the hip joint and presents specific risk patterns for labral injury. Prevention and training programs should be tailored to the movement demands of the athlete's sport.

In soccer and field hockey, the high volume of running, cutting, and kicking places significant demands on the hip. Soccer players demonstrate a high prevalence of FAI, which directly increases labral tear risk. Kicking mechanics that involve excessive hip extension and external rotation, combined with a lack of core control, create impingement at the anterior labrum. Training should emphasize hip and core strength to control the pelvis during kicking and cutting, along with eccentric hamstring and gluteal work to decelerate the leg during the follow-through. Goalkeepers, who perform repeated lunges and dives, should practice landing mechanics that avoid hip adduction and internal rotation at ground contact.

In dance and gymnastics, the emphasis on extreme ranges of motion—particularly hip external rotation (turnout) and flexion—creates a unique risk profile. Dancers frequently develop a combination of anterior impingement from forced flexion and internal rotation and posterior labral tearing from deep flexion and turnout. Prevention programs for dancers should include controlled range-of-motion training, isometric strengthening at end-range positions, and neuromuscular control exercises that maintain alignment while approaching the extremes of motion. The principle of "turnout from the hip, not the knee or foot" must be reinforced in every training session.

In running sports, including distance running, sprinting, and jumping events, the repetitive nature of the gait cycle creates cumulative load. Fatigue-induced form breakdown is a primary risk factor: as the runner fatigues, pelvic drop increases, hip adduction increases, and the femur internally rotates more during stance phase. Runners can use cadence cues (increasing steps per minute) to reduce step length and hip excursion, along with hip strengthening to maintain neutral alignment. Regular gait analysis on a treadmill or track can identify early signs of form deterioration.

In overhead sports like baseball, volleyball, and tennis, the hip plays a critical role in generating and transferring kinetic energy through the kinetic chain. A pitcher or server who lacks hip external rotation range must compensate through the lumbar spine, increasing the risk of both back injury and labral pathology. Hip mobility and rotational control exercises should be integrated into the training program for these athletes. The American Academy of Orthopaedic Surgeons has published sport-specific injury prevention guidelines that include hip-focused components for overhead athletes.

In combat sports and collision sports such as football, rugby, and mixed martial arts, direct trauma to the hip from contact is a significant risk factor. However, even in these sports, the majority of labral tears result from repetitive microtrauma rather than a single traumatic event. Strength and conditioning programs that emphasize hip stability in a wide base of support, along with landing and cutting mechanics, are essential for prevention.

Long-Term Benefits of Proper Biomechanics

The investment in biomechanical training for labral tear prevention yields benefits that extend far beyond the hip joint itself. Athletes who move with optimal mechanics experience improved performance, reduced injury risk across multiple joints, and a longer career span. The concept of preventive maintenance applies to the human body just as it does to equipment: a well-maintained machine performs better and lasts longer.

Performance improvements result from more efficient force transmission through the kinetic chain. When the hip is properly centered and the pelvis is stable, ground reaction forces are transmitted upward with minimal energy loss. Sprint times improve because the athlete can generate and transfer power more effectively. Jump height increases because the hip and knee can extend fully and explosively without compensating for instability. Agility and change-of-direction speed improve because the athlete can decelerate, plant, and accelerate with confidence and control. These performance gains are not separate from injury prevention—they are the direct consequence of the same biomechanical optimization.

Beyond the hip, proper mechanics protect adjacent joints. The knee benefits significantly from improved hip control: when the femur does not adduct and internally rotate excessively during landing and cutting, the patellofemoral joint experiences less stress, reducing the risk of patellofemoral pain syndrome and anterior cruciate ligament injury. The lumbar spine benefits from improved lumbopelvic control: when the pelvis remains level and the hip can rotate freely, the lumbar spine does not have to compensate for restricted hip motion. This reduces the risk of low back pain, disc pathology, and sacroiliac dysfunction. The contralateral hip also benefits because asymmetries in strength and mobility are corrected, preventing the contralateral joint from absorbing excessive loads.

For youth athletes, the long-term benefits are especially significant. The adolescent years are a critical window for developing movement patterns that persist into adulthood. During growth spurts, muscles and bones develop at different rates, creating temporary imbalances that increase injury risk. A structured program that emphasizes biomechanics during this period can prevent the development of faulty movement habits that would otherwise become entrenched and difficult to correct later. Furthermore, early intervention for hip pain can prevent the progression of labral pathology to secondary osteoarthritis, which is a serious long-term consequence of untreated labral tears. The OrthoInfo platform from the AAOS provides evidence-based guidance for parents, coaches, and young athletes on the principles of safe and effective training.

When to Seek Professional Help

Despite the best prevention efforts, an athlete may still develop hip symptoms that require professional evaluation. Persistent groin pain that does not resolve with 48 to 72 hours of activity modification, mechanical symptoms such as clicking or catching, and stiffness that limits sport performance warrant a comprehensive assessment. The athlete should not continue to train through these symptoms, as labral tears often progress over time with continued loading.

The evaluation should be performed by a sports physical therapist or a fellowship-trained orthopaedic surgeon with expertise in hip pathology. The assessment should include a thorough history, a movement screen, provocative testing for labral irritation, and a strength and range-of-motion examination. If clinical findings suggest a labral tear, advanced imaging is indicated. Magnetic resonance arthrography is the imaging study of choice, as it provides the highest sensitivity and specificity for detecting labral pathology. Ultrasound, while less sensitive, may be used for dynamic assessment when MRI is not available or contraindicated.

Conservative management is the first line of treatment for labral tears without mechanical symptoms that cause significant disability. This approach includes activity modification, physical therapy focused on correcting the underlying biomechanical deficits, and anti-inflammatory medications for symptom control. The success rate of conservative management varies widely depending on the tear characteristics and the athlete's ability to modify movement patterns. For athletes who fail conservative care or who have large, mechanically symptomatic tears, hip arthroscopy with labral debridement or repair is indicated. The surgical outcomes are generally favorable, with return-to-sport rates exceeding 80 percent in most series, but the key to long-term success is postoperative rehabilitation that addresses the movement dysfunction that caused the tear in the first place. Surgical repair without biomechanical retraining is associated with a higher risk of recurrence.

Conclusion

Proper biomechanics are not optional for athletes who wish to protect their hip joints and sustain high-level performance over a long career. The hip labrum is a vital structure that depends on optimal joint mechanics to function properly and maintain its integrity. When movement patterns break down—whether from muscle weakness, joint restriction, poor neuromuscular control, or faulty technique—the labrum bears the brunt of abnormal forces and becomes vulnerable to tearing. Understanding the specific biomechanical deficits that place the labrum at risk, and implementing systematic interventions to correct those deficits, represents the most effective strategy for prevention.

A comprehensive approach combines assessment, targeted strengthening and mobility work, neuromuscular retraining, and ongoing coaching feedback tailored to the demands of the athlete's sport. This approach does not require expensive technology or highly specialized expertise—many effective interventions can be implemented at the team or club level with appropriate training. What it does require is a commitment to movement quality as a fundamental component of athletic development, equal in importance to strength, conditioning, and skill training. Athletes who adopt this philosophy and integrate biomechanical optimization into their daily routine will not only reduce their risk of labral tears but also move better, perform better, and extend their athletic lifespan. The labrum is a small structure with a big job, and protecting it requires nothing less than a complete commitment to proper movement from the ground up.