private async void start_Click(object sender, RoutedEventArgs e)
        {
            await BandModel.InitAsync();

            Reset();
            _accelerometerModel.Init();
            _accelerometerModel.Changed += _accelerometerModel_Changed;
            synth = new SpeechSynthesizer();
            Speak("Let's go!");
            isAchievementUnlocked = false;
        }
        protected override async void OnNavigatedTo(NavigationEventArgs e)
        {
            Finish.IsEnabled         = true;
            WorkoutDetails.IsEnabled = true;

            var workoutId = WorkoutParams.workoutId;

            if (WorkoutParams.resetTimer == true)
            {
                App.workoutTimer          = new DispatcherTimer();
                App.workoutTimer.Interval = new TimeSpan(0, 0, 1);
                App.startTime             = DateTimeOffset.Now;
                App.workoutTimer.Start();
                CaloriesModel.startCalories = -1;
                CaloriesModel.calories      = 0;
                HeartRateModel.count        = 0;
                HeartRateModel.sum          = 0;
                HeartRateModel.peak         = 0;
                WorkoutParams.resetTimer    = false;
            }

            App.workoutTimer.Tick += dispatcherTimer_Tick;

            if (WorkoutParams.startNewWorkout || currentWorkout == null)
            {
                currentWorkout = await App.DefaultWorkoutsTable.LookupAsync(workoutId);

                m_nextExrciseIndex = 0;

                WorkoutParams.startNewWorkout = false;
            }
            if (WorkoutParams.isFinishedExercise)
            {
                m_nextExrciseIndex++;
                ExerciseParams.startNewExercise  = true;
                WorkoutParams.isFinishedExercise = false;
            }

            ExersiceIds = currentWorkout.ExercisesIds.Split(';').ToList();

            if (m_nextExrciseIndex >= ExersiceIds.Count())
            {
                StartExercise.IsEnabled  = false;
                StartExercise.Visibility = Visibility.Collapsed;
                NextEx.Text     = "Done";
                NextEx.FontSize = 30;
            }
            else
            {
                StartExercise.IsEnabled  = true;
                StartExercise.Visibility = Visibility.Visible;
                NextEx.FontSize          = 20;
                var fireAndForget = calculateNextExName(m_nextExrciseIndex);
            }

            // Calories
            await BandModel.InitAsync();

            _caloriesModel.Init();
            _caloriesModel.Changed += _caloriesModel_Changed;
            _caloriesModel.Start();
        }