Incremental Shuttle Walking Test
The incremental shuttle walking test (ISWT) was developed to simulate a cardiopulmonary exercise test using a field walking test.
Note: The ISWT is available from Dr Sally Singh, Department of Respiratory Medicine, Glenfield Hospital NHS Trust, Groby Road, Leicester LE3 9QP, UK or email: email@example.com.
- The patient is required to walk between two cones in time to a set of auditory beeps played on a CD.
- Initially, the walking speed is very slow, but each minute the required walking speed progressively increases.
- The patient walks for as long as they can until they are either too breathless or can no longer keep up with the beeps at which time the test ends.
- The number of shuttles (laps between the cones) is recorded. Each shuttle represents a distance of ten metres.
- The results of the ISWT can be used to prescribe the intensity of walking exercise (see Exercise Training section).
Standardisation of the ISWT is very important for obtaining meaningful outcomes.
The ISWT must be measured on two occasions to account for a learning effect. Please note that:
- The best result is recorded.
- If the repeat test is performed on the same day, 30 minutes rest should be allowed between tests.
- Debilitated individuals may require tests to be performed on separate days, but aim for tests to be less than one week apart.
- Only standardised instructions from the CD should be used. In contrast to the six-minute walking test, no encouragement should be given throughout the ISWT.
- A comfortable ambient temperature and humidity should be maintained for all tests.
- The walking track must be the same for all tests for a patient:
- Cones are placed nine metres apart.
- The distance walked around the cones is 10 metres.
The equipment needed to conduct the ISWT is identified in the attached checklist.
Before the ISWT
- Ensure that you have obtained a medical history for the patient and have taken into account any precautions or contraindications to exercise testing.
- Instruct the patient to dress comfortably and to wear appropriate footwear.
- Any prescribed inhaled bronchodilator medication should be taken within one hour of testing or when the patient arrives for testing.
- The patient should rest for at least 15 minutes before beginning the ISWT.
- Blood pressure.
- Heart rate.
- Oxygen saturation.
- Dyspnoea score.*
* Note: Show the patient the dyspnoea scale (e.g. Borg scale) and give standardised instructions on how to obtain a score.
During the ISWT
Follow the instructions on the CD, and use the following standard prompts:
o Each time the beep sounds:
"Increase your speed now.”
o Use the following prompt if the patient is less than 0.5 m away from the cone when the beep sounds.
“You’re not going fast enough; try to make up the speed this time.”
o Record each shuttle that is completed on the ISWT recording sheet.
o Monitor the patient for untoward signs and symptoms.
Ending the ISWT
The ISWT ends if any one of the following occur:
- The patient is more than 0.5 m away from the cone when the beep sounds (allow one lap to catch up).
- The patient reports that they are too breathless to continue.
- The patient reaches 85% of predicted maximum heart rate (maximum heart rate = 210 – 0.65 x age)
- The patient exhibits any of the following signs and symptoms:
- Chest pain that is suspicious of / for angina.
- Evolving mental confusion or lack of coordination.
- Evolving light-headedness.
- Intolerable dyspnoea.
- Leg cramps or extreme leg muscle fatigue.
- Persistent SpO2 < 85%.
- Any other clinically warranted reason.
At the End of the ISWT
- Seat the patient or, if the patient prefers, allow to the patient to stand.
Note: The measurements taken before and after the test should be taken with the patient in the same position.
- Immediately record oxygen saturation (SpO2)%, heart rate and dyspnoea rating.
- Two minutes later, record SpO2% and heart rate to assess the recovery rate.
- Record the total number of shuttles.
- Record the reason for terminating the test. The patient can be asked:
“What do you think stopped you from keeping up with the beeps?”
The patient should remain in a clinical area for at least 15 minutes following an uncomplicated test.
ISWT as an outcome measure
The change in the distance walked in the ISWT can be used to evaluate the efficacy of an exercise training program and / or to track the change in exercise capacity over time.
An improvement of 47.5 metres in ISWT indicates that patients with COPD are ‘slightly better’ and an improvement of 78.7 metres represents ‘better’ (Singh et al 2008).