 Complete the following phrase:  His personal best triple jump was 15.49 metres, achieved in August 1939 at Bislett stadion. With this he was a European record holder for a period, beating the old mark by Vilho Tuulos by one centimetre. Strøm also had a 15.82 metres jump in September 1939 in Gothenburg, albeit with an illegal wind assistance of about 8 ms. For comparison, 15.49 metres is better than the gold medal-winning results at the 1934, 1938, 