There are two fundamental principles involved in keeping the seventh-day Sabbath. First, it is a day of rest and, second, we are to uphold the spiritual intent of the day. God wants us to be renewed both physically and spiritually. Designed for this purpose, the Sabbath is a gift from God and not a burden. It is for our own well being (Mark 2:27).
When one is involved in playing sports on the Sabbath, it is generally a physically and mentally enervating experience for purely secular reasons—something contrary to the purpose of the Sabbath. In contrast to other days of the week, God says the Sabbath is holy time—time set apart as different from other time during the week (Genesis 2:3)—and it has a specific spiritual purpose.
We keep the Sabbath holy only by refraining from work or pursuits that are intended for the other six days of the week. If we were participating in a sport on the Sabbath, it would distract our attention from the intended purpose of the day. Furthermore, we would be using God's time for our own selfish pursuits and, therefore, we would no longer be keeping the Sabbath holy.
In this society that ignores God's Commandments, the Sabbath can be a test of our faith. But when we call it a delight and not a burden, it then becomes a great blessing to our lives and God rewards us richly (Isaiah 58:13-14). The Sabbath is a time for resting from our normal activities and focusing on spiritual priorities.