To complete the sentences accurately, I would need to analyze the shape and spread of the histogram. In a general case where a histogram has a few outliers or is skewed:
The distribution of the 50-meter freestyle times is best described as skewed. So, the median is a more appropriate measure of center than the mean.
If the distribution is symmetric or bell-shaped, the sentence could be different:
The distribution of the 50-meter freestyle times is best described as normal. So, the mean is a more appropriate measure of center than the median.
Please refer to the actual histogram to get the appropriate descriptors for your specific case.