What did Paul mean when he said he runs not as uncertainly?

Les explains that Paul uses the runner analogy to contrast temporary and eternal motivation. Athletes train temperately in food and drink to enhance body strength, but they do it to obtain a crown of leaves and vines that will die and amount to nothing. Paul says believers run the spiritual race for an incorruptible crown that lasts for all eternity. So when Paul says he runs not as uncertainly, Les teaches that Paul is not running without really knowing what he is after. He knows the prize, connected with knowing Him and the power of His resurrection. Paul refuses to just shadow box or beat the air; he will train himself spiritually to run the race of life and win the prize. Les also notes that the last verse about keeping under the body has been misconstrued because of the King James term, and Paul means keeping everything under control.