Why am I getting a null pointer error in my view model ASP.NET MVC

I am currently trying to read data from a database and send that data into a list so that I can display the data items in a list however, I am getting a null pointer error in my view near my foreach loop.

Controller:

public ActionResult Index()
    {

        try
        {
            connection.Open();
            SqlCommand myCommand = new SqlCommand("SELECT Firstname, ExerciseName, PR_Weight FROM Users, Exercises, PR WHERE Exercises.ExerciseID = PR.ExerciseID AND PR.Username = Users.Username AND Firstname = 'Evan' ", connection);
            SqlDataReader myReader = myCommand.ExecuteReader();
            Globals.PRList.Clear();
            while (myReader.Read())
            {
                PRViewModel pr = new PRViewModel();

                pr.PR_ID = (int)myReader["PR_ID"];
                pr.Username = myReader["Username"].ToString();
                pr.ExerciseID = (int)myReader["ExerciseID"];
                pr.PR_Weight = (int)myReader["PR_Weight"];
                pr.PR_Date = myReader["PR_Date"].ToString();
                pr.Exercises.exerciseID = (int)myReader["ExerciseID"];
                pr.Exercises.exercsieName = myReader["ExerciseName"].ToString();
                Globals.PRList.Add(pr);
            }
        }
        catch (Exception err)
        {

            ViewBag.Status = 0;
        }
        finally
        {
            connection.Close();
        }

        return View(Globals.PRList);
    }

Globals Class:

public static class Globals
{
    public static string myConnection = @"Data Source=TYRONSSPEEDYBOY\SQLEXPRESS02;Initial Catalog=PR_Tracker_DB1;Integrated Security=True";
    public static List<PRViewModel> PRList = new List<PRViewModel>();
}

Index View:

 @foreach (PRViewModel pr in Model)
{
<tr>
    <td>@pr.PR_ID</td>
    <td>@pr.Username</td>
    <td>@pr.ExerciseID</td>
    <td>@pr.PR_Weight</td>
    <td>@pr.PR_Date</td>

PRViewModel:

public PRViewModel()
    {
        Exercises = new ExerciseViewModel();
    }

    public int PR_ID { get; set; }
    public string Username { get; set; }
    public int ExerciseID { get; set; }
    public int PR_Weight { get; set; }
    public string PR_Date { get; set; }
    public ExerciseViewModel Exercises { get; set; }