Eystein Enoksen

Validity and reliability of the Newtest Powertimer 300-series® testing system

Abstract The aim of the present study was to assess the reliability and validity of the Newtest Powertimer 300-series® portable contact mat and photocells (Newtest Oy, Finland). The participants were 20 male soccer players aged 19.1±3.5 years. The validity and reliability of the Powertimer (contact mat and photocells) were assessed in a comparison of a laboratory testing method (force platform and photocells) and the Newtest Powertimer system. All participants were tested on 40-m sprint, countermovement jump, and squat jump. The results showed that the Powertimer was a reliable instrument for both jumping and running. The system did not show any marked systematic bias (P < 0.05) and the random error associated with it was negligible. A comparison of the laboratory testing method with the Powertimer revealed that the Powertimer contact mat and photocells had poor validity and the bias in measurement differed from that of the laboratory testing method (P < 0.05). The Newtest Powertimer testing system was shown to be a useful instrument for measuring jump height and running speed. However, if a comparison of overall values of jumping height is intended, it is important to use the same testing system, because different systems give different results. It is also advisable to use this equipment only if no other “gold standard” equipment is available.

The effect of high- vs. low-intensity training on aerobic capacity in well-trained male middle-distance runners.

Enoksen, E, Shalfawi, SAI, and Tønnessen, E. The effect of high- vs. low-intensity training on aerobic capacity in well-trained male middle-distance runners. J Strength Cond Res 25(3): 812-818, 2011-The purpose of this study was to examine the effect of 2 different intervention training regimes on &OV0312;o2max, &OV0312;o2max velocity (v&OV0312;o2max), running economy (RE), lactic threshold velocity (vLT), and running performance on a group of well-trained male middle-distance runners in the precompetition period. Twenty-six well-trained male middle-distance runners took part in the study. All participants were tested on &OV0312;o2max, v&OV0312;o2max, RE, lactate threshold (LT), vLT, and a performance test. The participants were matched according to their pretest results, then randomly assigned into 1 of 2 groups, a high-volume (70 km) low-intensity training group (HVLI-group); or a high-intensity low-volume (50 km) training group (HILV-group). No significant differences were found between the 2 groups on all measures both before and after the intervention period. Furthermore, the HILV-group had a marked increase in v&OV0312;o2max and vLT after the training period when compared with pretest. Both groups had a marked improvement in RE. The performance test showed that the HILV-group made 301 ± 886 m (1.0 ± 2.8 minutes) and the HVLI-group 218 ± 546 m (0.9 ± 1.8 minutes) in progress. The production of lactic acid was notably higher in the HILV-group (0.9 mmol) when compared with the pretest. The findings show that male middle-distance runners tested in this study improved in v&OV0312;o2max and vLT more when they train around LT, than training with low intensity for a short period of 10 weeks.

The Relationship Between Running Speed and Measures of Vertical Jump in Professional Basketball Players: A Field-Test Approach

Shalfawi, SAI, Sabbah, A, Kailani, G, Tønnessen, E, and Enoksen, E. The relationship between running speed and measures of vertical jump in professional basketball players: A field-test approach. J Strength Cond Res 25(11): 3088–3092, 2011—The purpose of this study was to examine the relationship between vertical jump measures and sprint speed over 10, 20, and 40 m in professional basketball players. Thirty-three professional basketball players aged (±SD) (27.4 ± 3.3 years), body mass (89.8 ± 11.1 kg), and stature (192 ± 8.2 cm) volunteered to participate in this study. All participants were tested on squat jump, countermovement jump, and 40-m running speed. The results show that all jump measures in absolute terms were correlated significantly to running performance over 10-, 20-, and 40-m sprint times. None of the jumping performance peak powers and reactive strength were found to have a correlation to running speed times in absolute term. Furthermore, all jump height measures relative to body mass except reactive strength had a marked and significant relationship with all sprint performance times. The results of this study indicate that while there is a strong and marked relationship between 10-, 20-, and 40-m sprint, there is also a considerable variation within the factors that contribute to performance over these distances. This may indicate that, separate training strategies could be implemented to improve running speed over these distances.

Percent Utilization of Oo2max at 5-km Competition Velocity Does Not Determine Time Performance at 5 km Among Elite Distance Runners

Støa, EM, Støren, Ø, Enoksen, E, and Ingjer, F. Percent utilization of &OV0312;o2max at 5-km competition velocity does not determine time performance at 5 km among elite distance runners. J Strength Cond Res 24(5): 1340-1345, 2010-The present study investigated to what extent maximum oxygen uptake (&OV0312;o2max) and fractional utilization (%&OV0312;o2max) in 5-km competition speed correlate with 5-km performance times among elite long distance runners. Eight elite long distance runners with 5-km performance times of 15.10 minutes ( ± 32 seconds) were tested for &OV0312;o2max during an incremental protocol and for %&OV0312;o2max during an 8-minute treadmill test at the velocity representing their 5-km seasonal best performance time. There was no correlation between fractional utilization and 5-km performance. The study showed no significant difference between &OV0312;o2max obtained during an incremental &OV0312;o2max test and %&OV0312;o2max when running for 8 minutes at the runners individual 5-km competition speed. The 5-km time was related to the runners &OV0312;o2max even in a homogenous high-level performance group. In conclusion, the present study found no relationship between fractional utilization and 5-km performance time. Training aiming to increase %&OV0312;o2max may thus be of little or no importance in performance enhancement for competitions lasting up to approximately 20 minutes.

Sprint Conditioning of Junior Soccer Players: Effects of Training Intensity and Technique Supervision

The aims of the present study were to compare the effects of 1) training at 90 and 100% sprint velocity and 2) supervised versus unsupervised sprint training on soccer-specific physical performance in junior soccer players. Young, male soccer players (17 ±1 yr, 71 ±10 kg, 180 ±6 cm) were randomly assigned to four different treatment conditions over a 7-week intervention period. A control group (CON, n=9) completed regular soccer training according to their teams’ original training plans. Three training groups performed a weekly repeated-sprint training session in addition to their regular soccer training sessions performed at A) 100% intensity without supervision (100UNSUP, n=13), B) 90% of maximal sprint velocity with supervision (90SUP, n=10) or C) 90% of maximal sprint velocity without supervision (90UNSUP, n=13). Repetitions x distance for the sprint-training sessions were 15x20 m for 100UNSUP and 30x20 m for 90SUP and 90UNSUP. Single-sprint performance (best time from 15x20 m sprints), repeated-sprint performance (mean time over 15x20 m sprints), countermovement jump and Yo-Yo Intermittent Recovery Level 1 (Yo-Yo IR1) were assessed during pre-training and post-training tests. No significant differences in performance outcomes were observed across groups. 90SUP improved Yo-Yo IR1 by a moderate margin compared to controls, while all other effect magnitudes were trivial or small. In conclusion, neither weekly sprint training at 90 or 100% velocity, nor supervised sprint training enhanced soccer-specific physical performance in junior soccer players.

A case study of the training of nine times New York marathon winner Grete Waitz

The purpose of the present study is to give a description of the exceptional running career of Grete Waitz (GW) and give special attention to the distribution of training volume and training intensity in two of her most successful years as an international long-distance and marathon runner. Training data are based on an analysis of GWs training diaries from her early start as a track and field athlete to her best performance years as a long-distance track runner and marathon runner. The main finding in this study was that GWs total running volume, in her best seasons, varied between 119–132 km · week−1 in the different meso-cycles of the training year. Her weekly training volume is far below the volume reported for the current female World Record holder for the marathon distance at the time of writing. Her training typically consisted of two daily sessions of continuous running (50–60 min) at a relatively high intensity. She did very few long interval training sessions, but she usually did one high-intensity session of shorter intervals/sprint training (strides) per week. In the season 1978–1979 she took part in 50 competitions (ranging from 800m to marathon) of which she won 48. Her best track performance in this season was her Nordic record in the 3000 m, 8:31.75 which would have been the best time in the world in 2011 and 2012.