Monday, September 30, 2002 - Physiology
Cross Country Ski Specific Core Strength and Stability Program: Assessment (Part 3 of 4)

- By: Ross McKinnon, PT

Part 1   Part 2

1. Modified Thomas Test - Flexibility

Test procedure:
The athlete sits at the edge of a table holding onto both knees. The athlete rolls onto their back keeping the knees bent. With the thoracic spine and pelvis on the table the athlete pulls one knee up to their chest until the lumbar spine flattens. The opposite leg (the leg to be tested) is positioned with the hip and knee flexed to 90°. The tester lowers the test leg to the table by extending the hip. Avoid allowing the leg to deviate away from the body, bending the non-test leg up to far, excessively flexing the spine or allowing the spine to extend off the table.

Normal: Thigh rests on the table with the knee flexed to 90° in the midline. Individual muscle tightness can be differentiated with the following tests. Shortened Rectus Femoris: Extending the knee allows the hip to lower closer to the table.
Shortened Iliotibial band/Tensor Fascia Lata: Abducting the thigh away from the midline allows the thigh to lower closer to the table. (Most common tightness) Shortened Iliopsoas: The hip remains above the table with both knee extension and hip abduction.

(Redrawn from Kendall 1993)

2. Hamstring Length - Flexibility

Test procedure:
The athlete lays on their back with the spine and pelvis in neutral alignment. Both legs are extended. With one hand the tester monitors the position of the spine and pelvis while lifting the leg with the other hand until resistance is felt. It is critical to keep the knee straight, not rotate the hip or allow the pelvis or spine to arch.

Normal: Ideally the knee should straighten to 80°.
Shortened Hamstrings: The legs extends less than 80°

(Redrawn from Kendall 1993)

3. Back to floor with arms overhead - Flexibility

Test procedure:
The athlete lies on their back maintaining a neutral spine position, both knees are bent. The athlete raises their arms above their head trying to contact the floor. Do not allow the spine to extend or arch away from the floor.

Normal: The athlete’s arms should contact the floor without excessive scapular movement.
Shortened Lats Dorsi/Pectoralis: Arms do not reach floor with back keeping neutral spine position. Tightness of Rotator cuff Muscles: Excessive movement of the scapula around the chest wall (protraction).

4. Breathing

Assessing breathing will determine both the pattern and if there are any muscle imbalances contributing to poor inspiration.
Test procedure A: Breathing pattern – Check for the type of breathing patterns in section while the athlete is relaxed in standing.
Test procedure B: With the athlete standing, flex the spine and instruct the athlete to take a breath in. Do the same with a corrected upright posture. There should be a noticeable improvement in the ability for the ribcage to expand during the upright stance. This is especially important in athletes with swayback posture.
Test procedure C: Face lying extension – Instruct the athlete to prop themselves up on their elbow or hands and try to expand the ribcage maximally with a deep breath. A restriction may indicate short abdominal muscles. Check that the right and left sides can expand maximally.
Test procedure D: Cat stretch position – On all fours lift the spine to the ceiling, maintain that position and sit down towards the heels without moving the arms. In that position try to expand the ribcage maximally with a deep breath. Check that the right and left sides can expand maximally. A restriction may indicate short latisimus dorsi and/or back muscles.

5. Upper abdominal Strength

Test procedure:
The athlete lays on their back with the spine and pelvis in neutral alignment. Both legs are extended. There are two phases to the trunk curl movement. The first component is trunk flexion and posterior tilt of the pelvis and spine. The second component is hip flexion. Ideally, the abdominals should flex the trunk first and then the hip flexors should be able to lift the trunk over the pelvis to come up to a sitting position. The abdominals must maintain the posterior tilt of the pelvis during raising and lowering. Avoid extension of the lumbar spine or lifting the feet off the floor. Avoid using momentum and ‘jerking’ during raising. See Table 2 below for grading.

6. Double leg lowering Strength

Test procedure:
The athlete lays on their back with the spine and pelvis in neutral alignment. Both legs are extended. Forearms are folded on the chest to ensure the elbows are not resting on the table for support. The tester assists lifting the legs to a vertical position. The athlete must posteriorly tilt the pelvis by contracting the abdominal muscles. The back must be held flat against the floor throughout the test. The athlete is then asked to lower the legs. The tester monitors the angle at which the pelvis and spine tilt away from the floor. Avoid excessive rectus abdominus bulging, breath holding and extension of the head and neck. See Table 2 below for grading.

TABLE 2 – Interpretation of abdominal tests
Grade Lower abdominals Upper Abdominals
50% 75 degrees keeps spine flexed but cannot sit up with forearms extended
60% 60 degrees keeps spine flexed and sits up with forearms extended
70% 45 degrees
80% 30 degrees keeps spine flexed and sits up with forearms folded on chest
90% 15 degrees
100% 0 degrees keeps spine flexed and sits ups with hands touching ears

7. Bent knee fall out/in - Stability

Test procedure:
The athlete lays on their back with the spine and pelvis in neutral alignment. Both legs are bent. The athlete is instructed to lower one leg out to the side.

Normal: the athlete should be able to dissociate the movements of the hip from the pelvis and lower back and lower the leg halfway to the floor.
Stability dysfunction: The athlete’s spine and pelvis rotate greater than _”. This problem is most likely one sided.
Shortened Adductors: The thigh cannot reach halfway. The athlete will complain of a pulling in their inner thigh.

8. Sidelying Hip Abduction – Stability

Test procedure: The athlete is positioned sidelying with their spine and pelvis in neutral alignment. The lower leg is slightly flexed for support. The uppermost leg is extended and slightly outwardly rotated (toes to the ceiling). The athlete is asked to lift the leg to the ceiling keeping is straight. Avoid allowing the hip to flex forward (this is the most .
common source of error), hitching the pelvis, or rotating the spine or pelvis backwards. Normal: The athlete can hold this position against maximal effort and can perform 10 leg lifts holding each for 10 seconds without tiring

9. Lateral Abdominal Test - Stability

Test procedure: The athlete finds their neutral spine position. The athlete should then be instructed to “draw their belly button into the spine” without using upper abdominals, pelvic tilting or diaphragmatic breath holding. It is very common for an athlete to try and stabilize by bulging of the rectus abdominus. The neutral spine must be maintained throughout the testing (by step 3 it is ok to flex the spine slightly). Check that the athlete can first perform the inner unit recruitment exercise (Level Ø) properly prior to testing higher levels.
Normal: athletes should attain level 4

Level Ø: Inner unit recruitment
Level 4: As above with heel touch
Level 1: Single leg knee lifts
Level 5: Lower both legs from 90° double leg heel slide
Level 2: Both knees to 90°. Lower one knee at a time, then up, repeat with opposite
Level 6: Lower both legs from 90°double leg lowering
Level 3: As above with heel slide
(From Comerford 2001)
10. Balance Test

Test procedure:
High Stance - The athlete stands in bare or sock feet. The athlete is asked to maintain balance on one leg for up to 15 seconds. The knee should be maintained straight but not locked. Check for compensations such as a tilting or rotating pelvis and hip, backward bending of the lumbar spine, knee joint rotation, foot flattening or toe clawing. Perform three trials per leg; score the average of the three. The most common compensations are to try and flatten the arch of the foot and adjustments at the ankle side to side. Flattening the arch translates to extra ‘edging’ on the inside of the gliding ski. Athletic Stance – As above with 25°-30° of knee flexion.
Level 1 Shaky
Level 2 Somewhat stable
Level 3 Stable (only minimal perturbations)

11. Dynamic Balance

Test procedure: Mark and ‘X’ on the floor with tape. The athlete balances on one leg. Ask the athlete to hop up and down on one leg 5-6 times on one leg. Check the ability for the athlete to maintain balance, maintain position over the ‘X’ with each hop and what, if any, compensation the athlete uses for balance. Common compensations will be excessive foot flattening and knee deviations to the inside. Use the above grading system.



Normal Tight Normal Tight

Thomas test


Arms overhead

On elbows Cat position


Trunk Curl Grade 50% 60% 70% 80% 90% 100%
Leg Lowering Grade 50% 60% 70% 80% 90% 100%

Right Left

Bent knee fall out/in

Sidelying Hip Abduction

Lateral Abdominal

Left leg
Right leg

Time Quality Time Quality

High stance

Athletic stance

Dynamic balance -

Ross McKinnon is a former ski racer now working as a physiotherapist at Rutland Physical Therapy in Kelowna, BC. His interests include improving an athletes performance through the use of exercise (both injured and non injured). For further questions he can be contacted at or at . This article is part three of his weekly four part series on cross country ski specific core strength and stability.

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