Looser fit makes heavier work pant fabric easier to maneuver in

My husband has a job that requires vigorous up and down movements throughout the day and generally the stiffer fabric of work pants hampers some of his ability to move easily - but the looser fit of this style makes it much easier for him to do so. Also, the reinforced knee helps make them more durable. His last batch made it for more than a full year, which is saying something given the beating he puts the fabric through each day. They also seem to be fairly resistant to small fly-away sparks from the torch.