Which tension is best?
Moderate tension (18 kg to 23 kg) offers more comfort, spin and power. The flip side is that you'll have less control and accuracy.
High tension (>23 kg) provides greater control and accuracy. It can, however, lead to tendinitis. You will also have less spin and power.
About monofilaments
For monofilament strings, Decathlon recommends a tension of between 19 kg and 22 kg. We strongly recommend against using monofilament strings for children under 15 to avoid injury. These strings are best for players who break strings in under 10 hours of play because they quickly lose their tension (20% loss within three hours of play).
About multifilaments
For multifilament strings, Decathlon recommends a maximum tension of 25 kg. These strings are recommended for people who are prone to tendinitis, youngsters, and people who don't break their strings often. Multifilament strings keep their tension very well and stay bouncy longer.
Tips from Decathlon
Your racket's performance depends 50% on your frame and 50% on your strings! Be sure to take the time to choose the right strings.
For players who break their strings a lot: change them as soon as they break.
For people who rarely or never break strings, Decathlon recommends changing them as many times per year as you play per week. E.g.: if you play once per week, change your strings once per year. If you play three times per week, change your strings three times per year.