Muscular Strength Testing ... If not using an equation, muscular strength tests using free ... The estimated load for a 10 RM 8 RM 6 RM 5 RM 4 RM 3 RM 2 RM.
Muscular Strength Testing Muscular Endurance Tests vs. Strength Tests Numerous maximal strength tests are available. However, for the majority of people muscular endurance tests are more practical as they can take less time to complete (unless you use a prediction equation such as the one below), are less painful and above all, they are safer. If not using an equation, muscular strength tests using free weights can be inaccurate if the subject starts the first attempt at too low a weight and has had several trials before momentary muscle failure occurs. In this case muscular strength may be underestimated. A properly conducted maximum strength test will however be more accurate than the predicted strength from an equation.
Endurance versus Strength The correlation between absolute strength and endurance has been reported to exceed 0.90 (de Vries, 1980; Invergo et. al., 1991). So clearly we are not talking about two independent measures of muscular function when we distinguish between strength and endurance. However, the correlation is not 1.00 and we know that specialised training can certainly focus on strength or endurance for any given individual. The very nature of strength tests makes them unsuitable for the non-athletic population, so the majority of testing you will be involved with is likely to be endurance testing. However, we will look at some less intense methods of estimating maximal strength from work with submaximal loads.
Dynamic versus Static (Isometric) Strength Tests Strength can be functionally defined as the maximal weight that a person can lift (i.e. one repetition maximal or 1-RM). There is some difficulty (and unsuitability due to potential for injury) in determining the 1-RM in a dynamic setting. Obtaining the 1-RM can be time consuming and fatiguing due to the hit-and-miss attempts at achieving one, and only one repetition. Isometric tests like the handgrip strength test (performed in Kin142) avoid this problem. However, most muscles groups are trained using dynamic isotonic or isokinetic equipment, and we know that strength can be joint-angle specific. Also many muscle groups are not used in an isometric manner and hence the results of an isometric test may not relate to function very well. The “most accurate?” method to determine dynamic strength is to attempt what you think is close to your 1-RM. If successful add 5 to 10 pounds to the weight and rest 2-3 minutes and try again, if unsuccessful this was your 1-RM, if successful repeat until unsuccessful. This can be fatiguing, and increase the chance of injury for those not weight training regularly, as mentioned above. I want you to estimate a weight you can bench press about 5 or 6 times. Perform the exercise until momentary muscular failure and use the equation below to estimate your 1-RM. The equation below should only be used for maximal repetitions from 1 to 10. I hope you guess accurately enough that you do not go over 10 repetitions. The higher the number of repetitions you can actually perform with the chosen weight, the larger the error in the estimate of your 1-RM.
1-RM = (weight lifted)/[1.0278 – (repetitions x 0.0278)]
From: Brzycki, M. (1993). Strength testing - Predicting a one-rep max from a reps-tofatigue. Journal of Physical Education, Recreation and Dance 64 (1), 88-90. This relationship is based on the relatively linear relationship between repetition maximal scores and the percentage of the 1-RM. In general, the predicted force of 1-RM is based on a decrease of around 2.5 per cent of the 1-RM for each increase in the number of maximal repetitions. The equation above has a sliding scale with a 2.78% reduction for the first increase to 2-RM and averages out to a 2.5% reduction at 10-RM. The table below gives you an idea of how this function works.
The estimated load for a
10 RM
8 RM
6 RM
5 RM
4 RM
3 RM
2 RM
is _____ of a 1 RM
75%
80.5%
86%
89%
91.7%
94.4%
97.2%
In case you are confused, let’s look at an example. If a 75 kg, 25-year-old male can bench-press 70 kg 6 times, the estimate of his 1-RM using the equation above is: 1-RM = 70 / [1.0278 - (6 x 0.0278)] = 70 / [1.0278 - 0.1668] = 70 / 0.861 = 81.3 kg Simple, n’est ce pas? It is even easier f you go to the ExRX website and use their OneRep Max calculator! The link to this page is one the Kin143 page. If we look this score up in the table “Bench Press Strength (lb) in Adult Men and Women” shown below he is around the 80th percentile in absolute strength. Next, divide this result by his body weight of 75 kg and you get the ratio of 1.08. In the table “Standard Values for Bench Press Strength in 1-RM / Body Weight Ratio” below we can see he would be classified as average. Notice that because you are dividing, it doesn’t matter whether you work in pounds or kilograms as long as both your 1-RM and your body weight are in the same units. Do the same with your leg press results. As with any course you only can get out what you are prepared to put in, so please try to do these tests. A trip to Piper’s Gym is free and your local community gym usually isn’t too expensive so please attempt to complete these tests. Be sure to warm up first!
Absolute Strength versus Relative Strength Again the issue of calculating absolute or relative values is relevant to muscular function testing (e.g. in the case of the LO2max, absolute in L/min and relative in ml/kg/min). If you were testing an athlete absolute strength values may make more sense, as for example a lineman has to tackle whatever size of individual he encounters. For the general population their strength to weight ratio is probably more relevant a measure to determine if they have a healthy muscular system capable of providing them adequate postural support and other strength requirements. For the strength tests below I have provided strength classifications based on both absolute and relative values whenever possible. Make sure you are using the same units (lbs or kg when calculating ratios).
Gettman (1988) recommends bench press and leg press for assessing strength of the upper and lower body, respectively. More detailed tests are available one that includes six test items: bench press, arm curl, lateral pull-down, leg press, leg extension and leg curl. See Heyward, V.H. Advanced Fitness Assessment & Exercise Prescription (second edition). Human Kinetics Books, Champaign, 1991, pages 106-108. Table below is from Hockey, Physical Fitness: The Pathway to Healthful Living, 1989. Note that it is U.S. data and hence in pounds not kilograms.
Bench Press Strength (lb) in Adult Men and Women Age (yrs) percentile 95 90 80 70 60 50 40 30 20 10 5 Mean SD
1.88 >1.76 >1.66 >1.56 Excellent Good 2.00-2.07 1.80-1.87 1.70-1.75 1.60-1.65 1.50-1.55 1.83-1.99 1.63-1.79 1.56-1.69 1.46-1.59 1.37-1.49 Average Fair 1.65-1.82 1.55-1.62 1.50-1.55 1.40-1.45 1.31-1.36 1.15 Excellent Good 1.54-1.62 1.35-1.41 1.26-1.31 1.13-1.25 1.08-1.14 1.35-1.53 1.20-1.34 1.12-1.25 0.99-1.12 0.92-1.07 Average Fair 1.26-1.34 1.13-1.19 1.06-1.11 0.86-0.98 0.85-0.91
