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| Author | Dario G. Liebermann; Murray E. Maitland; Larry Katz | ||||
| Title | Lower-limb extension power: How well does it predict short distance speed skating performance? | Type | Journal Article | ||
| Year | 2002 | Publication | Isokinetics and Exercise Science | Abbreviated Journal | |
| Volume | 10 | Issue  |
2 | Pages | 87-95 |
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| Abstract | This study was aimed to explore the relationship between lower limb extension power measured by isokinetic knee extensions (IK) and vertical jumps performed on a force plate (VJ) and speed skating (SS) sprint power measured by a laser device. Methods: Twenty elite short- and long-track speed skaters performed 100 m sprints followed by VJ and IK trials. Power-time curves were calculated off-line. Pearson correlation coefficients were used to determine the degree of association between the variables. Results: SS sprint power correlates strongly with VJ power (r=0.870; p<0.001) while IK power showed a weaker but significant correlation to both (r=0.707 and r=0.706, respectively; p<0.01). As expected, SS times at 15 m and 100 m were inversely associated with SS sprint power (r=-0.818 and r=-0.909; p<0.001) and VJ power (r=-0.730 and r=-0.763; p<0.001), and to a lesser degree with IK power (r=-0.602; r=-0.618; p<0.01). Conclusion: The analyses differentiate between methods of estimating power in speed skaters, and show a strong relationship between initial SS performance and muscular power. Given that 100 m split times strongly relate to final 500 m results (r=0.972; p<0.001, N=332), it is reasonable to believe that an initial power and a stable peak speed before the first curve may lead to achieving the winning edge in short SS events. A finding of particular interest is that isokinetic power results are correlated significantly with the practical outcomes of the performance in spite of the high specificity of the isokinetic testing method. |
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| Notes | Approved | no | |||
| Call Number | Serial | 62 | |||
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| Author | Dario G. Liebermann; Larry Katz | ||||
| Title | On the assessment of lower-limb power capability | Type | Journal Article | ||
| Year | 2003 | Publication | Isokinetics and Exercise Science | Abbreviated Journal | |
| Volume | 11 | Issue |
2 | Pages | 87-94 |
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| Abstract | Purpose: This study assessed the reliability and validity of different methods used to estimate lower-limb muscular power capability based on mechanical variables. For this purpose, vertical jumping was compared with isokinetic knee extensions and with power tests used by practitioners. Methods: Four groups of subjects (N = 106) were tested in different conditions. Group-I performed countermovement vertical jumps (CMJ) on a force plate followed by left and right knee extensions on an isokinetic device at 120, 180 and 240 deg�s-1. Group-II performed CMJ trials followed by 20-m sprints, hand-reach jumps and 1RM leg-press testing. Group-III carried out squat jumps (SJ) in addition to CMJ trials. Finally, Group-IV performed the CMJ test and was retested twice after a short inter-session interval (1–4 days) and after a long one (4.5–5 months). The Pearson correlation was used to assess the validity and reliability of CMJ (p ≤ 0.01, ). Results: Mean peak power during CMJ was correlated with sprint time (r = -0.882) and leg-press 1 RM (r = 0.797), but less with peak hand-reach height (r = 0.695; p ≤ 0.05). Isokinetic knee extension power showed also a significant correlation with CMJ power, but its strength depended on the angular velocity (Isok-120 r = 0.702; Isok-180 r = 0.737; Isok-240 r = 0.599). Test-retests showed a strong correlation after a short interval (r = 0.915) and after a long one (r = 0.890). Using the SJ technique did not have any effect on reliability (r = 0.914**). Conclusions: CMJ matches other methods used for testing lower-limb power capability. It is highly reliable and it allows a valid assessment of muscular power. Since CMJ is also simple and accurate to perform, it is the recommended method. |
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| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | ISBN | Medium | |||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | Serial | 63 | |||
| Permanent link to this record | |||||