Common Biomechanical Deficiencies Weaknesses Inflexibilities Postural Deficiencies

The biomechanical deficiencies are listed for precautionary measures only so they may be identified and possibly corrected in attempt to prevent athletic injuries during exercise or physical activity. These deficiencies are possible risk factors for injury and may only increase injury when combined with other risk factors. A physician may need to establish if a biomechanical deficiency is structural, muscular, neuromuscular, or due to some other pathology. The corrective exercises assume deficiencies are due to a muscular imbalance (flexibility and strength). Only a qualified physician should diagnose and give prescription for an existing injury. In some circumstances, an attempt to correct a biomechanical deficiency may irritate the injury and prolong recovery, particularly if certain therapy exercises are used inappropriately or initiated too soon after an injury has occurred. Even after an underlying biomechanical deficiencies has been improved, a preexisting injury may require the attention of a physical therapist under the advise of a physician to restore total functionality.

Abdominal WeaknessIncreased risk of lower back injury can occur during hip flexion, extension, stabilization and back extension activities. Erector Spinae muscles can hyperextend lower back more than usual if abdominal muscles are weak. The abdominal muscles tilt the pelvis forward, improving the mechanical positioning of the Erector Spinae, specifically when the lumbar spine becomes straight. When abdominal strength/endurance is not adequate to counter the pull of the antagonist Erector Spinae under load, these low back muscles are put at a mechanical disadvantage (active insufficiency) further placing additional stresses on these very same lower back muscles. Iliopsoas can pull on the spine during hip flexor activities if the abdominal muscles are weak. Risk is compounded when abdominal weakness is combined with hip flexor inflexibility.

Examples of affected exercises: Squat Deadlifts Military Press (standing) Lying Leg Raise (full extension): hands may

be placed under lower portion of glutes to decrease tilt of pelvis and subsequent hyperextension of spine.

Example preventative / corrective exercise: Crunch

1 / 16

Object 1

Hamstrings WeaknessIncreased risk of knee injury (instability) occur during knee extension activities, specifically when knees are flexed more than 90. When hip and knee are simultaneously extending during a compound movement, hamstrings counter the anteriorly directed forces of Quadriceps. Also see Knee Stability and Angle of Pull for force vector explanation. Hamstrings / Quadriceps strength ratios should be greater than 56% to 80% depending on the population tested.

Examples of affected exercises: Squat Leg Press

Example preventative / corrective exercises: Leg Curls Straight Leg Deadlift

Supraspinatus WeaknessIncreased risk of shoulder injury during shoulder flexion and abduction activities, specifically when the elbow travels below the shoulder during shoulder abduction. Risk is compounded with a winged scapula condition. Paradoxically, avoiding full range of motion (i.e. not initiating deltoid exercises from a fully adducted position) may not allow the Supraspinatus to be fully strengthened since it is more fully activated at these initial degrees of shoulder abduction/flexion. Once an injury has occurred, however, range of motion is typically restricted on the shoulder press. See shoulder abduction force vector diagram.

Examples of affected exercises: Shoulder Press Upright Row Lateral Raise

Example preventative / corrective exercises: Front Lateral Raise Lying Lateral Raise

2 / 16

Infraspinatus WeaknessIncreased risk of shoulder injury occurs during throwing and shoulder transverse flexion and transverse adduction activities, particularly when the elbow travels behind shoulder. Risk is compounded with a protracted shoulder girdle. The strong stabilizing and dislocating forces of the Pectoralis Major (Sternal and Clavical) is counteracted by the Infraspinatus, Teres Minor, and to a lesser extent, the rear deltoid and long head of the triceps brachii. This counter force is most crucial during:

initiation of a transverse adduction/flexion elbows behind shoulders stabilizing force

during the end of a throwing movement high deceleration dislocating forces required of the posterior cuff can

cause breakdown in their tendons near their humeral attachment.

External rotation-muscular endurance / internal rotation-muscular endurance should be greater than 70%.

Examples of affected exercises with suggestions for high risk individuals:

Bench Press : Bring bar lower on chest, keeping elbows closer to sides.

Chest Press : Elevate seat so elbows are closer to sides Range of motion may need to be limited so elbows do not go behind shoulders

Example preventative / corrective exercises: Lying External Rotation Rows

Erector Spinae WeaknessIncreased risk of lower back injury occur during lumbar spine extension or stabilization activities. Back extension exercises involving complete lumbar spine range of motion have demonstrated primarily excellent or good results for those with chronic lower back pain. Excellent or good results by diagnosis: 76% Mechanical / Strain, 72% Degenerative, 78% Disc Syndrome, 75% Spondylo. In contrast, McGill condemns the use of isolated lumbar spine exercise apparatuses and argues erector spinae endurance is more important than strength. See Low Back Debate.

Examples of affected exercises Straight Leg Deadlift Squat Deadlift

Example preventative / corrective exercises: Back Extension (novice) Cable Row (with spinal articulation) (novice to intermediate) Stiff Leg Deadlift (advanced)

3 / 16

Vastus Medialis WeaknessIncreased risk of knee injury (chondromalacia) occurs during knee extension activities. The patella becomes laterally displaced with the pull of the vastus lateralis. This patella tracking problem can produce wear on the inferior patellar surface. Greater pain is usually experienced during leg extension activities in which the knee is a greater than a 20 to 30 degree angle. Avoiding full range of motion (i.e. not locking out) during Quadricep exercise may not allow the Vastus Medialis to be fully strengthened since it is more fully activated at these final degrees of knee extension.

Examples of affected exercises: Leg Press Squat Leg Extension

Example preventative / corrective exercises: Single Leg Extensions (last 20 degrees of extension) Leg Press (last 20 degrees of extension)

Hip Abductor WeaknessOne hip can sag when weight is shifted to one leg. Possible increase risk of Iliotibial band friction syndrome (ITBFS) when combined with Gluteus Maximus and/or Tensor Fascia Latea Inflexibility (Fredericson, et. al. 2000).

Examples of affected exercises: Lunges | Step-Ups Running | Stair Climber | Gauntlet | Elliptical

Example preventative / corrective exercises: Lever Seated Hip Abduction Eventually reintroduce effected exercises in a progressive manor

4 / 16

AHIP external rotators

Other Names Six Deep Lateral Rotator Hip Muscles

Heads1. Piriformis 2. Gemellus Superior 3. Obturator Internus 4. Gemellus Inferior 5. Obturator Externus 6. Quadratus Femoris

MovementHip

External Rotation [1, 2, 3, 4, 5, 6 ] Transverse Abduction [1, 5 ] Internal Rotation [1] (see comments)

AttachmentsOrigin

Sacrum Anterior [1 ] Sacrotuberous Ligament [1 ]

Ischium Posterior Portions

Ischial Spine [2 ] Ischial Tuberosity

Posterior Portion [4 ] External Border [6 ]

Obturator Foramen [5, 6 ] Ischium and Pubis

Inside Surfaces and Obturator Membrane [3 ]

5 / 16

Insertion

Femur Greater Trochanter

Medial Surface [2, 3, 4 ] Superior/Medial Surface [1 ] Posterior Surface

Quadrate Tubercle [6 ] Trochanteric Fassa [5 ]

CommentsGemellus Superior [2 ] and Gemellus Inferior [4 ] also known collectively as Gemelli. Insertion of piriformis is high up on greater trochanter, so it assists in external rotation from anatomical position, but when it hip is flexed, piriformis assists in internal rotation of hip.

6 / 16

COMMON ORTHOPAEDIC INFLEXIBILITIESHamstrings Inflexibility

Increased risk of lower back injury during hip extension activities when knees are straight. If hip flexion (eccentric phase of hip extension), is inhibited by hamstrings inflexibility, the lumbar spine may compensate by flexing more than usual. The risk of injury is increased if the lumbar spine is not accustomed to this movement or workload. Also see Active Insufficiency.

Examples of affected exercises: Straight Leg Deadlift Good Morning Barbell Bent-over Row

Example assessments Active Lying Knee Extension Test Passive Lying Leg Lift Test

Example preventative/corrective exercise: Seated Hamstrings Stretch Lying Hamstrings Stretch

Gluteus Maximus or Adductor Magnus Inflexibility

Increased risk of lower back injury during hip extension activities when knees are bent. After complete flexion of the hip (eccentric phase of hip extension), the lumbar spine will flex if movement is continued. The risk of injury is increased if the lumbar spine is not accustomed to this movement and workload. Until flexibility can be restored, recline leg press back support to furthest position and base hip flexion range of motion criteria just before hips tilt. Also see Full Squat Flexibility Q&A.

Examples of affected exercises: Leg Press Squat Single Leg Squat

Example Assessment Deep Squat Test

Example preventative/corrective exercise:

Glute Stretch Adductor Magnus Stretch

Hip Flexor InflexibilityIncreased risk of lower back injury during hip flexion and extension and overhead standing activities. During

7 / 16

extension activities, the lower back can hyperextend more than usual if the hip cannot fully extend. During hip flexion activities, the Iliopsoas can hyperextend spine during hip flexor activities. Risk is compounded when hip flexor inflexibility is combined with abdominal weakness.

Examples of affected exercises: Military press (standing) Decline Sit-up Lunge (rear leg) Lever Back Extension (fulcrum near hip)

Example assessments Lunge Test Thomas Test

Example preventative/corrective exercises: Kneeling Hip Flexor Stretch Quadriceps Stretch

Shoulder Transverse Abduction / Transverse Extension InflexibilityTypically due to insufficient flexilibility of pectoralis muscles. Results in decreased range of motion during chest exercises. High risk for behind the neck exercises particularly when combined with external shoulder rotation inflexibility. exacerbated and often accompanied by protracted shoulders girdle. Excluding cases with particular orthopedic problems (e.g.: infraspinatus weakness), participants should be encouraged to perform chest exercises through THIER full range of motion; shoulder transverse extension / hyperextension until a slight stretch is felt. Since the shoulder can typically hyperextend further than it can transverse extend, the exerciser performing a bench or chest press will be able to bring bar closer to body when elbows are positioned closer to body (shoulders more abducted).

Example of affected exercises: Bench Press Chest Press Chest Flies Behind Neck Shoulder Press Rear Pull-down

Example assessment Passive Chest Flexibility Assessment

Example of preventative/corrective exercises: Straight Arm Chest Stretch

Shoulder FlexionIn ability to raise arm forward overhead or undue exertion required position arm in vertical position.

8 / 16

Examples of affected exercises:

Dumbbell Shoulder Press Cable Shoulder Press Overhead Triceps Exercises Overhead Squat Power Clean

Example assessments Shoulder mobility (open

hands) Shoulder mobility (closed

hands) Prone Shoulder Flexion Overhead Deep Squat

Example of preventative/corrective exercises: Bent-over Lat Stretch (on chair or bench) Wall Lat Stretch Overhead Squat Dumbbell Shoulder Press

Shoulder External Rotation InflexibilityIncreased risk of shoulder injury during activities involving external rotation of the shoulder. Risk is compounded with a winged scapula condition or kyphosis. Until full range of motion is restored, individuals with external rotation inflexibility should be advised to perform pull-downs and shoulder press with the bar in front of the head. Those with more severe cases should perform overhead presses with angled back support (eg: 100-110 incline bench).

Examples of affected exercises: Behind Neck Shoulder Press Lever Shoulder Press (torso upright

facing away from lever) Rear Pull-down Lever Fly (on pec deck) Overhead Squat Snatch

Example assessment Passive Shoulder External Rotation Assessment

Example preventative/corrective exercises: Subscapularis Broom Stick Stretch

9 / 16

Shoulder Internal Rotation InflexibilityIncreased risk of shoulder injury during activities involving internal rotation of the shoulder. When the shoulder is flexed and internally rotated, pressure can be created between the insertion of the supraspinatus and acromion or coracoacromial ligament. Incidentally, pain in this position can be indicative of impingement or rotator cuff tendinitis (Hutton & Julin 1997). Tight internal rotators can contribute to protracted shoulders.

Examples of affected exercises: Upright Row (narrow grip)

Example assessment Passive Shoulder Internal Rotation Assessment

Example preventative / corrective exercises: Infraspinatus Broom Stick Stretch

Iliotibial Band TightnessIncreased risk of lateral knee injury during knee extension activities. Iliotibial band friction syndrome (ITBFS) is a cause of diffuse tenderness over the lateral knee. While weight bearing during knee flexion, the Tensor Fascia Latea contracts to assist the other hip abductors stabilize the pelvis from lateral movement and the Gluteus Maximus extends the hip for forward locomotion. Both the Tensor Fascia Latea and the Gluteus Maxiums can place tension on the Iliotibial tract which produces repetitive friction on the lateral epicondyle. Furthermore, hip abductors weakness can exacerbate this pull on the Iliotibial tract by allowing the hip to sag slightly when standing on a single leg, or during locomotion (Fredericson, et. al. 2000).

Examples of affected exercises: Lunges Step-Ups

Example assessment Ober's Test

Example preventative / corrective exercises:

Tensor Fasciae Latea Stretch

Gluteus Maximus Stretch Lever Seated Hip

Abduction

Ankle Dorsiflexion InflexibilityDorsiflexion flexibility is required during the lower phases of the squat and leg press, so Ankle Dorsiflexion inflexibility can make it difficult to perform squat and leg press exercises in full range of motion. If the range of motion of the ankle is limited, hip flexion may be exaggerated and knee flexion is often inhibited. To maintain normal range of motion in both the hip and knee, the heel may have a tendency to leave the

10 / 16

floor or platform.

Examples of affected exercises with suggestions for affected individuals until range of motion is restored

Leg Press : place feet higher on the platform Squats : wider stance or elevate heels slightly on board or weight plates Range of motion may need to be restricted so heels do not raise at lower portion of

exercise Example Assessments

Deep Squat Active Bent Knee Foot Raise Test

Example preventative / corrective exercises: Gastrocnemius Stretch Soleus Stretch Calf Raise Calf Press

Plantar Fasciitis & Foot Dorsiflexion InflexibilityHigh incidences of plantar flexion strength deficits and dorsiflexion range of motion limitations are associated with Plantar Fasciitis. Plantar Fasciitis is a common overuse syndrome occurring in runners and walkers. This syndrome is associated with microtears in the plantar fascia at its insertion into the calcaneus. If allowed to progress to the point when bone spur (calcium deposit) forms on the underside of the calcaneous (heel bone), surgery may be required. Individuals with excessive pronation (feet rolling inward), flat feet, or knocked knees have increased risk for plantar fasciitis. These conditions force the plantar fascia to stretch more during weight bearing activities placing increased pressure where it attaches to the heel bone. High arches are also associated with plantor faciitis.

Examples of affected exercises

Walking (particularly upon awakening) Running Jumping

Example Preventative Exercises

Seated Plantar Fasciitis Stretch Can Foot Roll

11 / 16

COMMON POSTURAL DEFICIENCIESStanding Postural Muscles

The diagram to the right illustrates how the body is held erect. The thick black lines represent the principal muscles involved in standing. The vertical dotted line indicates the center of gravity. Note this line falls behind the axis of rotation of the hip and in front of the knee. This renders the ligaments of the joints tense, which are represented by dotted lines passing in front of the hip (ilio-femoral) and behind the knee (posterior ligament).

Posterior Pelvic TiltSometimes referred to as flat back, posterior pelvic tilt involves the reduction of the natural lumbar curvature. This posture is characterized by the shortening of the hip extensors (Hamstrings & Gluteus Maximus inflexibility), tight abdominals, and lax hip flexors. Sitting on the back of the hips may indicate a posterior pelvic tilt. It is rarely brought about by lack of muscular strength. The posterior pelvic tilt is less common as the anterior tilt as seen with lordosis.

Examples of affected exercises: Leg Press Squat Straight Leg Deadlift

Example preventative / corrective exercises: Hip Flexor: Lever Hip Flexion Hamstrings: Lying Hamstring Stretch Gluteus: Seated Glute Stretch Abdominal: Abdominal Stretch

LordosisPelvis is positioned forward and downward. Hips are slightly flexed and lumbar spine is excessively hyperextended. Hip flexors, erector spinae are short. Abdominal, hamstrings, gluteus maximus muscles may be weak. Increased risk of lower back injury during standing or lying hip extension, flexion, or stabilization activities, and weighted overhead activities. See abdominal weakness and hip flexor inflexibility.

Examples of affected exercises: Squat Hack Squat , Roman Chair Sit-up Military Press (standing)

12 / 16

Example preventative / corrective exercises: Hip Flexor: Kneeling Hip Flexor Stretch Erector Spinae: Lower Back Stretch Abdominal: Crunches Hamstrings: Leg Curl Gluteus: Seated Leg Press

KyphosisExaggerated anterior-posterior curvature of the vertebral column, most often involves an excessive forward bending in the thoracic area. Kyphosis occurs in older adults, particularly women with osteoporosis and osteoarthritis. Kyphosis is sometime accompanied with other posterior problems such as posterior or anterior pelvic tilt (compensates for altered line of gravity) and protracted shoulder girdle (unrelated). Kyphosis makes it difficult to include overhead exercises particularly when combined with a winged scapula condition or shoulder external rotation inflexibility.

Examples of affected exercises: Shoulder Press Seated Triceps Extension Front Squat Overhead Squat

Corrective exercises for gravity induced kyphosis: Strengthening of thoracic vertebral column extensors Stretching of thoracic vertebral column flexors

Forward Head PostureAn anterior positioning of the cervical spine is characteristic of forward head posture, or protracted neck. Forward head posture may make it more difficult to perform exercises with the bar in front of head or neck. Evaluate neck position at night since elevating head too high with additional pillows may act as a continuous neck stretch throughout the evening exacerbating the forward head posture.

Examples of affected exercises: Shoulder Press

Corrective exercises for gravity induced kyphosis: Strengthening of cervical vertebral column extensors

Isometric Neck Retraction Stretching of cervical vertebral column flexors

Neck Retraction

13 / 16

Winged ScapulaMedial border or inferior angle of scapula protrudes slightly from body. A winged scapula condition may be accompanied by a protracted shoulder girdle. Risk of shoulder injury is compounded with a supraspinatus weakness or an external shoulder rotation inflexibility. Because of the forward tilt of the scapula, complete flexion or external rotation of the shoulder may be seemingly restricted. A winged scapula condition indicates a serratus anterior weakness. The rhomboids may be weak and the pectoralis minor may be short. A winged scapula is considered normal posture in young children, but not older children and adults.

Examples of affected exercises: Shoulder Press Pullovers Pull-downs

Example preventative / corrective exercises: Incline Shoulder Raise Cable Row Pectoralis Minor Stretch Wall Lat. Stretch

Protracted Shoulder GirdleThe shoulders are pulled forward. Medial border of the scapula may also protrude slightly from body. Increased risk of shoulder injury during shoulder transverse flexion and transverse adduction activities, specifically when elbow travels behind shoulder. Scapula protraction can also decrease width of subacromical space, possibly increasing risk of subacromical impingement (Solem-Bertift E, et al. 1993). In both cases, risk of shoulder injury is compounded with a infraspinatus weakness. Possible limited range of motion during retraction of the shoulder girdle. A protracted shoulder girdle may be accompanied by a winged scapula condition or transverse adduction / flexion inflexibility. The subscapularis and Pectoralis minor and clavicular & sternal heads of the pectoralis major muscles may be short. The trapezius (middle fibers) and particularly the rhomboids may be weak if the medial borders of the scapula also protrude slightly from body.

14 / 16

Examples of affected exercises: Bench Press Chest Press Flies Barbell Hack Squat Upright Row (particularly close grip) Front Lateral Raise (with internal shoulder rotation)

Example preventative / corrective exercises: Cable Row or Lever Row (do not hold protracted position) Doorway Modified Chest Stretch Wall Shoulder Girdle Stretch Doorway Subscapularis Stretch Work through full range of

motion on chest exercises just to position that

slight stretch is felt.

If lying on one's side, position upper arm under head (with or without pillow in between) since lying on one's side with one's arm down or in front (protracting shoulder girdle) may act as a continuous stretch throughout the night exacerbating this condition.

Likewise, those with a protracted shoulder girdle should avoid stretches that protract the shoulder such as Rear Delt Stretches or holding a protracted position during rowing resistive exercises.

Normalizing this postural deficiency can improve mechanics of the shoulder and provide a fuller appearance throughout the chest.

ScoliosisMediatorial curve of the vertebral column.

Congenital scoliosis develops before birth and is caused by a defect in the formation of the spinal column. Either parts of the vertebrae are missing or vertebrae fail to separate, leading to asymmetry and unequal growth of the spine. Scoliosis develops because one side grows more than the other, causing the spine to curve.

Degenerative scoliosis occurs in adults for two main reasons. First, scoliosis may have started when the patient was younger (starting as adolescent idiopathic scoliosis) and may have worsened with increasing age. The second degenerative, or de novo, type of scoliosis starts after 40 years old and is thought to be the result of arthritis or degeneration of the spine, with changes in alignment caused by degeneration of the discs and the facet joints. Degenerative curves might also progress a few degrees per year, particularly if the patient has osteoporosis and a sequential collapse of the vertebrae.

In about 80% of all scoliosis cases there is no known cause. This type of scoliosis is called idiopathic scoliosis.

15 / 16

Idiopathic scoliosis can be described as early onset or late onset. It is surprisingly common although most patients need no treatment or do not realise that they have a curved spine. Curves measuring up to 11 are considered normal. Observation is the mainstay of management in most patients, and bracing or plaster casts are sometimes used. Surgery is reserved for those curves that are symptomatic or are at high risk of becoming symptomatic because of the size that they have reached.

The term neuromuscular scoliosis is used to describe curvature of the spine in patients with any disorder of the neurological system. Common categories include cerebral palsy, spina bifida, muscular dystrophies, and spinal cord injuries. In most of these children the unifying feature is weakness of the trunk. Nerves can be affected from the brain (eg, cerebral palsy) down to the spinal cord (eg, poliomyelitis). If the muscles do not work, such as in spinal muscular atrophy or Duchenne muscular dystrophy, then scoliosis can develop.

Patients with these conditions often develop scoliosis or kyphosis (round back), or both. As they grow and their trunk muscles get weaker, the spine progressively collapses, producing a long, C-shape scoliosis. The curvature of the spine worsens during growth spurts. These curves tend to be progressive, with the rate of progression becoming worse during rapid growth. For children confined to a wheelchair, progressive curves can affect the child's ability to be seated comfortably, thereby affecting their quality of life and function. A progressive or large curve can affect a childs pulmonary function by leading to collapse of the torso and raising of the diaphragm, which reduce the space for the lungs. This reduction in space can manifest itself in recurrent pneumonia (chest infection).

Scheuermanns kyphosis is a structural curvature of the thoracic or thoracolumbar spine that develops before puberty and deteriorates during adolescence. It is the second most common cause of back pain in children and adolescents with spondylolysis (defect in the vertebral arch) and spondylolisthesis (displacement of a vertebra or the vertebral column in relation to the vertebrae below).

The age at onset is about 1012 years, but a subset of patients present in adulthood. The condition occurs in 0.4-8.3% of the population, though its true incidence is probably underestimated because it is often attributed to poor trunk posture. It affects equally male and female patients.

Scoliosis can occur as part of a recognised syndrome. For example, people diagnosed with Marfans syndrome, Rett syndrome, or Beales syndrome are likely to develop scoliosis.

Extensive research and recent experience of certain physical and complementary therapists supports ideas around alternative scoliosis long-term management and possible treatment using alternative or complementary therapies such as gentle bone setting or other joint corrections methods. One of the examples of a safe non-manipulative method is the Dorn Method or Dorn Therapy. Dorn Method may be the only existing safe method suitable for non-medical environment which does not involve any manipulations or forced movements or use of excessive leverage in the process of correcting alignment of any vertebral joints. It involves active therapy and self-help routines for long-term management. Dorn Method can potentially be taught to sensitive carers who could use it frequently on their family members, clients or patient as appropriate.

16 / 16

Common Biomechanical DeficienciesAbdominal WeaknessHamstrings WeaknessSupraspinatus WeaknessInfraspinatus WeaknessErector Spinae WeaknessVastus Medialis WeaknessHip Abductor WeaknessOther NamesHeadsMovementAttachmentsCommentsHamstrings InflexibilityGluteus Maximus or Adductor Magnus InflexibilityHip Flexor InflexibilityShoulder Transverse Abduction / Transverse Extension InflexibilityShoulder FlexionShoulder External Rotation InflexibilityShoulder Internal RotationInflexibilityIliotibial Band TightnessAnkle Dorsiflexion InflexibilityPlantar Fasciitis & Foot Dorsiflexion InflexibilityStanding Postural MusclesPosterior Pelvic TiltLordosisKyphosisForward Head PostureWinged ScapulaProtracted Shoulder GirdleScoliosis