PHP - inserccion mutiple

<form method="post">

    <h3 class="bg-primary text-center pad-basic no-btm">Agregar Registro</h3>

    <table class="table bg-info"  id="tabla">

        <tr class="fila-fija">

            <td><input required name="nombre[]" placeholder="ID Alumno"/></td><br>

            <td><input required name="apellido[]" placeholder="Nombre Alumno"/></td><br>

            <td><input required name="email[]" placeholder="Carrera"/></td>

            <td><input required name="telefono[]" placeholder="Grupo"/></td>

            <td class="eliminar"><input type="button"   value="Menos -"/></td>

        </tr>

    </table>

    <div class="btn-der">

        <input type="submit" name="insertar" value="Agregar" class="btn btn-info"/>

        <button id="adicional" name="adicional" type="button" class="btn btn-warning"> Más + </button>

    </div>

</form>

if($insertar){

for($i=0;$i<$count;$i++){

$sql1="UPDATE $t_persona SET nombre='$nombre[$i]', apellido='$apellido[$i]', email='$email[$i]' WHERE id='$id[$i]'";

$result1=mysql_query($sql1);