Protocol	Miles per hour	Grade (%)	Metabolic equivalents
Standard Bruce protocol (3 minutes per stage)
Stage 1	1.7	10	4
Stage 2	2.5	12	7
Stage 3	3.4	14	10
Stage 4	4.2	16	13
Stage 5	5.0	18	16
Stage 6	5.5	20	NA
Stage 7	6.0	22	NA
Modified Bruce protocol (3 minutes per stage)
Stage 1	1.7	0	2
Stage 2	1.7	5	3
Stage 3	1.7	10	4
Stage 4	2.5	12	7
Stage 5	3.4	14	10
Stage 6	4.2	16	13
Stage 7	5.0	18	16
Stage 8	5.5	20	NA
Stage 9	6.0	22	NA
Naughton protocol (2 minutes per stage)
Stage 1	1.0	0	1
Stage 2	2.0	0	2
Stage 3	2.0	3.5	3
Stage 4	2.0	7	4
Stage 5	2.0	10.5	5
Stage 6	2.0	14	6
Stage 7	2.0	17.5	7