It could be due to water retention from adding in strength training, which is a good thing and will eventually go away. This Ask the Experts page addresses this in more detail: www.sparkpeople.com/community/ask_the_expe
. You want to keep strength training as regular strength training increases the size and strength of the muscle fibers. It also strengthens the tendons, ligaments, and bones. All of these changes have a positive impact on your physical fitness, appearance, and metabolism, while reducing the risk of injury and decreasing joint and muscle pain. So it is important to continue to strength train, even if you aren't seeing the results right away.