Prohibited, no. Discouraged, yes.
The Church of Jesus Christ of Latter-day Saints recognize the Sabbath on Sundays. Sundays are set aside from things of the 'world' and members are encouraged to attend Church services and focus their activities on doing those things that would help them to draw closer to Jesus Christ.
Other appropriate activities could include studying the scriptures, serving others, visiting the sick, gathering with family, etc...
"The Sabbath is the Lord's day, set apart each week for rest and worship. In Old Testament times, God's covenant people observed the Sabbath on the seventh day of the week because God rested on the seventh day when He had created the earth. After the Resurrection of Jesus Christ, which occurred on the first day of the week, the Lord's disciples began observing the Sabbath on the first day of the week, Sunday (see Acts 20:7). "
Thank you for "Asking a Mormon".