MileSplit Staff Apr 17, 2026 PRO See the rest of this article Access the complete article with MileSplit PRO. Subscribe to keep reading Already a subscriber? Log in. Improvement Rankings: Top South Dakota Boys 400m marks compared to their season’s best performances from 2025. Most Improved - 400 Meter Dash Comparing 2026 season to 2025 season Rank Improved Athlete/Team Class 2025 PR 2026 PR 1 -10.53 Chris Radford Irene-Wakonda High School 2028 1:25.06 1:14.53 2 -9.75 Sam Baker Rapid City Stevens High School 2028 1:15.96 1:06.21 3 -8.25 Gavin Kipp McCook Central/Montrose High School 2027 1:02.58 54.33 4 -5.96 Teagan Bush Mt. Vernon/Plankinton High School 2028 1:07.03 1:01.07 5 -5.66 Jackson Molstad Oldham Ramona High School 2030 1:06.89 1:01.23 ...