Puedo guardar cadenas en mis preferencias guardadas pero tengo dificultades para guardar los botones de opción.

public class PersonalDetailsf extends Activity {

    private SharedPreferences sharedPreferences;  

    private RadioGroup radioGroup;
    private RadioButton radioSexButton;
    private RadioButton rdoMale;

Aquí está mi en Crear:

    sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

    String strAge = Integer.toString(age);
    String strHeight = Integer.toString(height);
    String strWeight = Integer.toString(weight);

    name = loadSavedPreference("name");
    strAge = loadSavedPreference("strAge");
    strHeight = loadSavedPreference("strHeight");
    strWeight = loadSavedPreference("strWeight");

    etName.setText(name);
    etAge.setText(strAge);
    etHeight.setText(strHeight);
    etWeight.setText(strWeight);

Esto está en mi onCLick detrás de un botón, donde estoy usando el botón de radio y guardando las cadenas:

            Name = etName.getText().toString();
            age = (int) Double.parseDouble(etAge.getText().toString());
            height = (int) Double.parseDouble(etHeight.getText().toString());
            weight = (int) Double.parseDouble(etWeight.getText().toString());


            int selectedId = radioGroup.getCheckedRadioButtonId();

            radioSexButton = (RadioButton) findViewById(selectedId);
            rdoMale = (RadioButton) findViewById(R.id.rdoMale);

            if(rdoMale.isChecked())
            {
                BMR = 10 * weight + 6.25 * height - 5 * age + 5;

            }
                else
            {
                    BMR = 10 * weight + 6.25 * height - 5 * age -161;

            }


            //Save Preferences
            String strAge = Integer.toString(age);
            String strHeight = Integer.toString(height);
            String strWeight = Integer.toString(weight);

            name = etName.getText().toString();
            savePreference("name",name);

            strAge = etAge.getText().toString();
            savePreference("strAge",strAge);

            strHeight = etHeight.getText().toString();
            savePreference("strHeight",strHeight);

            strWeight = etWeight.getText().toString();
            savePreference("strWeight",strWeight);