jounal-muscular strength testing

7/30/2019 Jounal-Muscular Strength Testing

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Muscular Strength Testing

Muscular Endurance Tests vs. Strength TestsNumerous 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 andabove all, they are safer. If not using an equation, muscular strength tests using freeweights can be inaccurate if the subject starts the first attempt at too low a weight andhas had several trials before momentary muscle failure occurs. In this case muscularstrength may be underestimated. A properly conducted maximum strength test willhowever be more accurate than the predicted strength from an equation.

Endurance versus StrengthThe correlation between absolute strength and endurance has been reported to exceed0.90 (de Vries, 1980; Invergo et. al., 1991). So clearly we are not talking about twoindependent measures of muscular function when we distinguish between strength and

endurance. However, the correlation is not 1.00 and we know that specialised trainingcan certainly focus on strength or endurance for any given individual. The very nature ofstrength tests makes them unsuitable for the non-athletic population, so the majority oftesting you will be involved with is likely to be endurance testing. However, we will lookat some less intense methods of estimating maximal strength from work with sub-maximal loads.

Dynamic versus Static (Isometric) Strength TestsStrength can be functionally defined as the maximal weight that a person can lift (i.e. onerepetition maximal or 1-RM). There is some difficulty (and unsuitability due to potentialfor injury) in determining the 1-RM in a dynamic setting. Obtaining the 1-RM can be timeconsuming 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) avoidthis problem. However, most muscles groups are trained using dynamic isotonic orisokinetic equipment, and we know that strength can be joint-angle specific. Also manymuscle groups are not used in an isometric manner and hence the results of anisometric test may not relate to function very well.

The most accurate? method to determine dynamic strength is to attempt what you thinkis close to your 1-RM. If successful add 5 to 10 pounds to the weight and rest 2-3minutes and try again, if unsuccessful this was your 1-RM, if successful repeat untilunsuccessful. This can be fatiguing, and increase the chance of injury for those notweight training regularly, as mentioned above.

I want you to estimate a weight you can bench press about 5 or 6 times. Perform theexercise until momentary muscular failure and use the equation below to estimate your1-RM. The equation below should only be used for maximal repetitions from 1 to 10. Ihope you guess accurately enough that you do not go over 10 repetitions. The higherthe number of repetitions you can actually perform with the chosen weight, the larger theerror in the estimate of your 1-RM.

1-RM = (weight lifted)/[1.0278 (repetitions x 0.0278)]


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From: Brzycki, M. (1993). Strength testing - Predicting a one-rep max from a reps-to-fatigue. Journal of Physical Education, Recreation and Dance 64 (1), 88-90.

This relationship is based on the relatively linear relationship between repetition maximalscores and the percentage of the 1-RM. In general, the predicted force of 1-RM is basedon a decrease of around 2.5 per cent of the 1-RM for each increase in the number ofmaximal repetitions. The equation above has a sliding scale with a 2.78% reduction forthe first increase to 2-RM and averages out to a 2.5% reduction at 10-RM. The tablebelow 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, lets look at an example. If a 75 kg, 25-year-old male canbench-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, nest ce pas? It is even easier f you go to the ExRX website and use their One-Rep 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 Womenshown below he is around the 80th percentile in absolute strength. Next, divide thisresult by his body weight of 75 kg and you get the ratio of 1.08. In the table StandardValues for Bench Press Strength in 1-RM / Body Weight Ratio below we can see hewould be classified as average. Notice that because you are dividing, it doesnt matterwhether 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 todo these tests. A trip to Pipers Gym is free and your local community gym usually isnttoo expensive so please attempt to complete these tests. Be sure to warm up first!

Absolute Strength versus Relat ive StrengthAgain the issue of calculating absolute or relative values is relevant to muscular functiontesting (e.g. in the case of the LO2max, absolute in L/min and relative in ml/kg/min). Ifyou were testing an athlete absolute strength values may make more sense, as forexample a lineman has to tackle whatever size of individual he encounters. For thegeneral 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 adequatepostural support and other strength requirements. For the strength tests below I haveprovided strength classifications based on both absolute and relative values wheneverpossible. Make sure you are using the same units (lbs or kg when calculating ratios).


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Gettman (1988) recommends bench press and leg press for assessing strength of theupper and lower body, respectively. More detailed tests are available one that includessix test items: bench press, arm curl, lateral pull-down, leg press, leg extension and legcurl. 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 k ilograms.

Bench Press Strength (lb) in Adult Men and Women

Age (yrs)


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Standard Values for Bench Press Strength in 1-RM / Body Weight Ratio

Age

20-29 30-39 40-49 50-59 60+

Rating Men

Excellent >1.26 >1.08 >0.97 >0.86 >0.78Good 1.17-1.25 1.01-1.07 0.91-0.96 0.81-0.85 0.74-0.77

Average 0.97-1.16 0.86-1.00 0.78-0.90 0.70-0.80 0.64-0.73Fair 0.88-0.96 0.79-0.85 0.72-0.77 0.65-0.69 0.60-0.63

Poor 0.55

Good 0.72-0.77 0.62-0.65 0.57-0.60 0.51-0.53 0.51-0.54

Average 0.59-0.71 0.53-0.61 0.48-0.56 0.43-0.50 0.41-0.50Fair 0.53-0.58 0.49-0.52 0.44-0.47 0.40-0.42 0.37-0.40

Poor 1.56Good 2.00-2.07 1.80-1.87 1.70-1.75 1.60-1.65 1.50-1.55

Average 1.83-1.99 1.63-1.79 1.56-1.69 1.46-1.59 1.37-1.49

Fair 1.65-1.82 1.55-1.62 1.50-1.55 1.40-1.45 1.31-1.36

Poor 1.15

Good 1.54-1.62 1.35-1.41 1.26-1.31 1.13-1.25 1.08-1.14

Average 1.35-1.53 1.20-1.34 1.12-1.25 0.99-1.12 0.92-1.07Fair 1.26-1.34 1.13-1.19 1.06-1.11 0.86-0.98 0.85-0.91

Poor

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