function computeMaxRm()
{
	var rc = document.getElementById('rc').value;
	var wl = document.getElementById('wl').value;
	var rs = document.getElementById('rs');
	var MaxRm = 0;
	
	//formula: 1RM = [1 + (0.0333 x reps completed)] x weight lifted
	maxRm = (1 + (0.0333 * rc) ) * wl;
	
	if( rc != '' && wl != '' ) {rs.value = maxRm.toFixed(2);}
}

function computeMaxRmPercent()
{
	var rc = document.getElementById('prc').value;
	var wl = document.getElementById('pwl').value;
	var rs = document.getElementById('prs');
	var MaxRmPc = 0;
		
	
	//formula: %1RM = 1RM x percentage (60% = 0.6)
	maxRmPc = rc * (wl / 100)
	
	if( rc != '' && wl != '' ) {rs.value = maxRmPc.toFixed(2);}
}


function computeBMR()
{
	var rc = document.getElementById('brc').value;
	var wl = document.getElementById('bwl').value;
	var rs = document.getElementById('brs');
	var Bmr = 0;
	var fatWeight = 0;	
	var leanMass  = 0;
	
	
	fatWeight = rc * (wl / 100);
	leanMass  = rc - fatWeight;
	Bmr = 370 + (21.6 * leanMass);
	
		
	if( rc != '' && wl != '' ) {rs.value = Bmr.toFixed(2);}
}

function computeBMI()
{
	
	var rc  = document.getElementById('irc').value;
	var wl  = document.getElementById('iwl').value;
	var rs  = document.getElementById('irs');
	var BMI = 0;
	
	//formula: Body Mass Index = body weight/(height in metres)2
	wl = wl / 100;
	BMI = rc / (wl * wl);
	if( rc != '' && wl != '' ) {rs.value = BMI.toFixed(2);}
	
}


function computeIdealBodyWeight()
{
		
	var rc  = document.getElementById('ibwrc').value; // curent weight
	var iw  = document.getElementById('ibwwl').value; // current % body fat
	var wl  = document.getElementById('ibwbf').value; // ideal % body fat
	var rs  = document.getElementById('ibwrs'); // result
	var ibw = 0; // Ideal Body Weight
	var clw = 0; // Current lean weight

	// Current lean weight = current weight - (current %body fat as decimal x current weight)
	// Ideal body weight = current lean weight/(1-desired body fat as decimal)         
	
	clw = rc - ((iw / 100) * rc);
	ibw = clw / (1 - (wl / 100));

	if( rc != '' && iw != '' && wl != '' ) {rs.value =ibw.toFixed(2);}
}


function computeEffectiveHeartRate()
{
	var age  = document.getElementById('age').value;
	var result  = document.getElementById('result');
	var hr67  = document.getElementById('hr-67');
	var hr78  = document.getElementById('hr-78');
	var hr89  = document.getElementById('hr-89');
	var hr91  = document.getElementById('hr-91');
	var mhr = 0;
	
	mhr = 220 - age;
	hrv67 = mhr * 0.65;
	hrv78 = mhr * 0.75;
	hrv89 = mhr * 0.85;
	hrv91 = mhr * 0.95;

	if( age != '') {
		result.value = mhr.toFixed(2);
		hr67.value = hrv67.toFixed(2);
		hr78.value = hrv78.toFixed(2);
		hr89.value = hrv89.toFixed(2);
		hr91.value = hrv91.toFixed(2);
		}
}

function computeWeeksIdealBodyWeight()
{
	
	var rc  = document.getElementById('ibrc').value;
	var iw  = document.getElementById('ibdw').value;
	var wl  = document.getElementById('ibaw').value;
	var rs  = document.getElementById('ibrs');
	var ibw = 0;
	
	// formula : (current weight - ideal weight)/average
	              // or expected weight loss per week = linear time frame (in weeks)
				  //Actual time frame = linear time frame x 1.1
		
	ibw = ((rc - iw) / wl ) * 1.1;		  
	if( rc != '' && wl != '' && iw != '' ) {rs.value = ibw.toFixed(2);}
	
}


function computeCaloriesForWG()
{
	
	var rc  = document.getElementById('wgrc').value;
	var wl  = document.getElementById('wgwl').value;
	var rs  = document.getElementById('wgrs');
	var calForWL = 0;
	
	//formula: Daily Metabolic Rate + 500 Calories = Calories for Gains
	//         Daily metabolic rate = BMR x factor
	
	calForWl = (rc * wl) + 500;
	if( rc != '' && wl != '' ) {rs.value = calForWl.toFixed(2);}
}


function computeCaloriesForWL()
{
	
	var rc  = document.getElementById('wlrc').value;
	var wl  = document.getElementById('wlwl').value;
	var rs  = document.getElementById('wlrs');
	var calForWL = 0;
	
	//formula: Daily Metabolic Rate - 500 Calories = Calories for Gains
	//         Daily metabolic rate = BMR x factor
	
	calForWl = (rc * wl) - 500;
	if( rc != '' && wl != '' ) {rs.value = calForWl.toFixed(2);}
}


function computeVO2Max()
{
	
	var wl  = document.getElementById('vmwl').value;
	var rs  = document.getElementById('vmrs');
	var VO2Max = 0;
	
	//formula: VO2 max = (distance in metres covered in 12 minutes - 505)/45
	VO2Max =  (wl - 505) / 45 ;
	
	if( wl != '' ) {rs.value = VO2Max.toFixed(2);}
}