Van Alphen won the silver medal at the 2007 Summer Universiade and finished eleventh at the 2007 World Championships. In 2005, he became Belgian champion in the decathlon. He was the first Belgian decathlete to pass the 8000 points limit.
In 2008, Van Alphen was a competitor in the decathlon of the Beijing Olympics, but did not finish all the events due to injury.
He was just below the 8000-point mark at the 2010 Hypo-Meeting, where he came 13th, then he set a personal best score of 8072 points to finish fifth at the 2010 European Championships in Barcelona. Continuing in that vein, he set a best in the men's heptathlon at the 2011 European Athletics Indoor Championships, taking ninth place with a total of 5938 points. Turning to the outdoor circuit, he improved a number of event bests at the Hypo-Meeting (including the 100 metres, high jump and long jump) and ended the competition in eleventh place with 8045 points. At the 2011 TNT - Fortuna Meeting in Kladno he put together his best series of results: following a best of 66.21 m in the javelin, he moved up four places in the final 1500 metres to take the runner-up spot behind Leonel Suárez with a decathlon personal best of 8120 points.
|Hans Van Alphen|
|Full name||Hans Van Alphen|
|Born|| 12 January 1982
|Height||6 ft 3 in (1.91 m)|
|Weight||203 lb (92 kg)|
|Sport||Track and field athletics|
|2005||Belgian Championship||Izegem, Belgium||1st||Decathlon||7064 pts|
|2006||Nordrhein-Mehrkampfmeisterschaften||Wesel, Germany||3rd||Decathlon||7411 pts|
|2007||Universiade||Bangkok, Thailand||2nd||Decathlon||8047 pts|
|World Championships||Osaka, Japan||11th||Decathlon||8034 pts|
|2008||Olympic Games||Beijing, China||-||Decathlon||DNF|
|2010||European Championships||Barcelona, Spain||5th||Decathlon||8072 pts|
|2011||Hypo-Meeting||Götzis, Austria||11th||Decathlon||8045 pts|
|TNT - Fortuna Meeting||Kladno, Czech Republic||2nd||Decathlon||8120pts|
|Décastar||Talence, Frane||1st||Decathlon||8200 pts|
|2012||Hypo-Meeting||Götzis, Austria||1st||Decathlon||8519 pts|
|Olympic Games||London, England||4th||Decathlon||8447 pts|
|Décastar||Talence, Frane||1st||Decathlon||8293 pts|