INTRODUCTION Exercise testing is an...

INTRODUCTION

Exercise testing is an essential part of management of populace with cardiopulmonary disease. It is used to diagnose the cause of symptoms or exercise limitation, assess exercise capacity, assess the factors that contribute to exercise limitation, assess the ne for specific therapy and the reply to such therapy, and prescribe exercise.1 mostly commonly, physical therapists use the rises of exercise testing to prescribe and assess the meanings of exercise training. Laboratory-based, externally paced, incremental exhibitions (GXT) are considered the gold standard in exercise testing.2,3 However, the equipment and personnel penuryed to administer such tests limit their use. These trials can also be intimidating and self-same debilitated patients may not be able to perform them adequately. Field experiments such as the 6-minute walk criterion (6MWT) and the incremental shuttle walk trial (ISWT) have been developed as alternatives to the GXT

The 6MWT is the mostly popular field test of exercise performance. It is simple to administer, requires little equipment, and its self-paced nature makes it acceptable to patients. This standard has been shown to be a reliable measure of distance walked when it is waysed according to standardized performance criteria.4 The longitudinal dimensions of the hallway used for the walk,5 the instructions given to the subject6 the adumbration and amount of encouragement given,6 and the number of learning trials4 have all been shown to affect standard performance. A recent survey of pulmonary rehabilitation programs in the United States and Canada demonstrated that practices regarding the performance of self-paced, fixed-time walking trials were poorly standardized.7 This recommends that the validity and reliability of these exhibitions typically used in clinical practice would not be equivalent to deductions that are reported in well controll studies. The comes of the 6MWT have been used to estimate oxygen uptake (VO^sub 2^) through using metabolic equations.8 Unfortunately, this estimate will not be accurate if walking spe varies significantly during the trial or the subject stops to rest

The ISWT was perform the operations indicated ined to overcome the problems associated with fixed-time, self-paced walking proofs such as the 6MWT. It is an externally-paced, incremental, symptom-limited maximal experiment based on the 20-m shuttle move test that was designed from Leger and Lambert9 to assess fitness in healthy adults. Singh et al10 adapted the proof for use with people with chronic obstructive pulmonary disease (COPD)

ADMINISTRATION

The ISWT is simple to administer and requires little equipment. Patients are required to walk along a 10-m course that is marked from 2 cones set at 05 m from each extreme point (Figure 1). Placement of the cone render certains that patients avoid abrupt changes in direction. Walking spe is place by an audio signal in succession a tape cassette. The accuracy of the timing signal is assessed at the beginning of the trial using a one minute calibration period included at the beginning of the tape. The tape also includes standardized instructions to the patient.

Patients begin the ISWT when they hear a signal forward the cassette. The initial pace is 05 m/ (112 mph) A single beep upon the tape signals when the patient should be at the cone at the expiration of the walking course. The walking spe increases by way of 0.17 m/s at each minute of the standard The change in speed is indicated on a triple beep from the cassette tape. The number of shuttle (10-m lengths) increases by dint of 1 each time the spe of walking increases. For instance, patients thorough 3 shuttles, each lasting 20 s in level 1 and 4 shuttle lasting 15 s each, in level 2. The tester who stands beside the 10-m course, does not give encouragement during the proof If subjects walk faster than the required spe they are told, before starting the trial to remain at the cone until they hear the beep to indicate the divert The test ends when the patient is exhausted or too breathless to continue or when the patient is more than 05 m from the cone when the inflect signal sounds. Singh et al10 and Morales and colleagues11 the two reported that subjects did not have difficulty coordinating the required changes in spe with the signals forward the audio cassette. There is a maximum of 12 flushs in the test. A chart included with the cassette identifies the number of shuttle and spe of walking, in m/ and mph at each level

VALIDITY AND REPRODUCIBILITY

Peak oxygen consumption (VO^sub 2^peak) measured during a GXT is considered to be an objective measure of functional exercise capacity.12,13 Singh et al14 examined the relationship between distance walked during the ISWT and VO^sub 2^peak measured during a graded treadmill experiment in a group of patients with moderate to accurate COPD (FEV^sub 1^ = 14 L) to assess the validity of the newly make knowned test. They reported a linear relationship between the 2 variables with r = 088 gymnast et al15 noted a capable relationship (r = 0.73) between the maximum distance cloaked in the ISWT and VO^sub 2^peak obtained during an incremental, period ergometer test (CET) in persons with COPD (FEV^sub 1^ = 289 ?± 79% predicted) and similar disease severity. lately Moloney et al16 examined the relationship between VO^sub 2^peak and distance concealed in the ISWT in patients with idiopathic pulmonary fibrosis. Initially, the authors compared the conclusions of the ISWT performed in a corridor with arises obtained from a treadmill equivalent of the ISWT. They demonstrated a significant correlation between the distances upon the 2 tests (r = 091) and a robust relationship between VO^sub 2^peak in succession the treadmill equivalent of the ISWT and the distance walked during the ISWT (r = 074) Similar correlations have been reported when the ISWT was used to assess family with chronic heart failure (CHF) Morales and his colleagues11 assessed exercise capacity in folks with CHF (ejection fraction