Chin-up strength tests: does stature matter?

AIM: Many organizations place high value on employee physical fitness and use standardized physical fitness tests (PFT) to quantify it. The chin-up strength test is an example of such a test. Participants' anecdotal reports raise some concern that the latter is inherently biased against tall individuals. A demonstration that tall individuals are less likely than short individuals to achieve maximum score on a chin-up strength test, and modified scoring tables that equalize this likelihood across the stature range are sought. METHODS: A statistical summary of 85 chin-up test outcomes is analyzed for likelihood of maximum scores as a function of stature. Scoring tables modified by reducing the number of chin-ups required for maximum score in a ratio inverse to a fixed power of the stature ratios are introduced. RESULTS: Statistical analysis shows that short individuals are more likely to achieve maximum chin-up test scores (P<0.05). Stature adjusted scoring tables are shown to neutralize this trend. CONCLUSION: Current scoring standards for chin-up strength tests favor short statures. Bias-free chin-up strength tests can be achieved by using stature-adjusted scoring tables. Similar bias problems may exist for other strength tests.

"Slinky" coils for neuromagnetic stimulation.

Future advances in neuromagnetic stimulation depend significantly on the design of coils with improved focality. Although in the absence of internal current sources, no true focusing of magnetically induced currents is possible, improvements in the focality of current concentrations passing through an area of biologic tissue are achievable through variations of the shape, orientation and size of neuromagnetic stimulating coils. The "butterfly" and the "4-leaf" coils are two examples of planar designs which achieve improved focality through centralization of the maximum coil current and peripheral distribution of the return currents. We introduce the "slinky" coil design as a 3-dimensional generalization of the principle of peripheral distribution of return currents and demonstrate its advantages over planar designs.

Post-stroke autonomic nervous system function: palmar sympathetic skin responses thirty or more days after cerebrovascular accident.

We studied sympathetic nervous system (SNS) function after cerebrovascular accident (CVA) by measuring hypothenar sympathetic skin responses (SSR) to normal or hemiplegic arm electrical stimulation. We anticipated SNS function after CVA to be asymmetric and selected null hypotheses of bilaterally symmetric SSR latencies and amplitudes irrespective of side of stimulation and/or recording. Thirteen patients between ages 44 and 77 years (median 59) were tested between 1 and 72 months (median 15) after CVA. Hypothenar recording and dorsal reference surface electrodes were used. Amplifier bandwidth was set from 0.5 to 100 Hz. Gain was adjusted to allow adequate recognition of the waveforms. Sweep speed was set to 500ms/div. Stimulus width was set to 0.2 ms and intensity was increased stepwise from 10mA initially until optimum responses were obtained. Nonparametric statistics were used to analyze the data. SSRs were present in all patients on both the normal and the hemiplegic sides irrespective of the side of stimulation. Median SSR latency recorded homolaterally to the stimulus site was found to be 80ms shorter than median SSR latency recorded heterolaterally. Median SSR latency in left hemiplegics was found to be 16% longer than in right hemiplegics. Otherwise, neither side of hemiplegia, side of stimulation, side of recording nor any paired combination thereof were found to be significant. Our finding of bilaterally obtainable SSRs after CVA diverges from that of Uncini and colleagues but presumably only reflects the difference in poststroke chronology between the respective samples.

Ultrasound velocity in fixed human liver: empirical anova and regression modelling on histologically assessed abnormalities.

Anova and "dummy variables" least squares regression methods are used to investigate the dependence of ultrasound propagation velocity on the presence or absence of fat and on the rank ordered level of cirrhosis in fixed human liver. Cirrhosis is found to affect velocity in a nonlinear fashion, while fat depresses the velocities toward lower values. Quantifications of these effects and statistical analyses of their magnitudes are presented. The results represent a contribution toward the empirical understanding of the effects of tissue abnormalities on the velocity of ultrasound propagation in fixed human tissues.