At the 2005 European Indoor Championships her last jump was measured to 6.96 metres, which would have secured her the gold medal by a comfortable margin. However, Kappler admitted to the referees that she could not possibly have jumped 6.96 m, which would be 30 cm further than her personal best at the time. Video analysis confirmed the mismeasurement and the jump was ruled invalid. The silver medal was won in 6.64 m, while Kappler remained with 6.53 m. She was later awarded a bronze medal for fair play.
At the 2007 European Indoor Championships she finished fourth, equalling her indoor personal best of 6.63 metres. Her personal best jump is 6.90 metres, achieved in July 2007 in Bad Langensalza. Her partner is the Austrian decathlete Klaus Ambrosch.
|1999||European U23 Championships||Gothenburg, Sweden||—||NM|
|2002||European Indoor Championships||Vienna, Austria||15th (q)||6.20 m|
|2003||World Championships||Paris, France||14th (q)||6.50 m|
|2004||World Indoor Championships||Budapest, Hungary||14th (q)||6.47 m|
|Olympic Games||Athens, Greece||8th||6.66 m|
|2005||European Indoor Championships||Madrid, Spain||3rd||6.53 m|
|World Championships||Helsinki, Finland||19th (q)||6.35 m|
|2007||European Indoor Championships||Birmingham, United Kingdom||4th||6.63 m|
|World Championships||Osaka, Japan||5th||6.81 m|
|2009||World Championships||Berlin, Germany||25th (q)||6.29 m|
|2010||World Indoor Championships||Doha, Qatar||12th (q)||6.37 m|
|European Championships||Barcelona, Spain||17th (q)||6.50 m|
|2011||World Championships||Daegu, South Korea||14th (q)||6.48 m|