<p>No problem. 
If you have closely related activities (say, in the area of music), create one EC called “Music” and say in the description “See Additional Information”. Then create a section in additional information that says something like “EC - Music” and bullet out your activities, awards, etc. Use bullets and be concise, though. Something like:</p>
<ul>
<li>Violin since age 5. </li>
<li>X High School Symphony Orchestra (violin) - 9th - 12th.<br></li>
<li>Section lead - 11th & 12th.</li>
<li>Blue ribbon at Solo & Ensemble - 10th & 11th</li>
<li>Concert choir - 10th & 11th</li>
<li>Pit orchestra (viola) - 4 musicals for X High School and one community theater pit orchestra</li>
</ul>
<p>In general, if you have ECs you are putting some detail in the additional information section for, use bullets and be concise.</p>