Soft and elastic jacket

A soft and elastic jacket is provided. No less than 70 percent of the body circumference of the soft and elastic jacket is composed of an elastic weft knitted fabric, when the soft and elastic jacket is in a motionless state without being worn. The elastic weft knitted fabric is produced by knitting 5ˆ¼15% weight of elastic yarns with the rest of non-elastic yarns, and it has a basis weight of 140-200 g/m 2 . The elastic weft knitted fabric has a tightness index of not greater than 0.8 and a recovery stress of 0.3ˆ¼1.3 N at an elongation range of 30ˆ¼80%. The respiratory quotient is not greater than 1.05, when a person wearing the soft and elastic jacket exercises at an intensity of less than 7 Mets and a body exercise amount of not greater than 25 Mets·hr for an exercise time of less than 6 hrs. The soft and elastic jacket has a clothing pressure of 0.6 kPa or less in a motionless state, and 2.5 kPa or less in a motion state.