Effects of training at 90 vs. 100 % sprint speed on repeated-sprint ability in high level junior soccer players

Background: Repeated sprint ability (RSA) is one of many important determinants for optimal performance in soccer. In the later years, several training studies have examined how to improve this parameter for gaining an optimal performance on the court. No studies have before examined the effect of training at lower intensities. Thus, the aim of this study was to examine if there were any improvements in RSA when training repeated sprint once in a week for seven weeks on different intensities and if the improvements on RSA were the same when training on lower intensity. Methods: 41 well-trained male soccer players of age (±SD) 16.7 (± 1.0) years, body mass 71.1 (± 9.4) kg, and stature 181.2 (±6.1) cm participated in the study. They were randomized either to the 100 % intensity group (100 % group) (n=16), the 90 % intensity group (90 % group) (n=15) or the control group (CON) (n=10). In addition to normal training, the 100 % group and the 90 % group completed 1 repeated sprint training session per week for a total of 7 weeks. The 100 % group performed 15 laps (20 meters) on 100 % intensity with one minute breaks between them. The 90 % group performed 30 laps (20 meters) on 90 % intensity with one minute between them. Before and after intervention, performance was assessed by a repeated 20 m *15shuttle sprint ability test, where mean and best times were measured. A yo-yo intermittent recovery test (IR1) and counter movement jump (CMJ) test was also conducted. Results: Within-group results showed statistical improvements for 100 % group in steplength (SL), step frequency (SF) and lactate. Between-group differences showed no statistically marked improvements for 100 % group or 90 % group against CON in any of the parameters. The effect of the training was only trivial to small in the performance parameters. Conclusion: Taking the results in this study into consideration, it can’t be recommended to train 20 meter repeated sprint for gaining improvements in RSA for young high level soccer players. Other training methods could be preferred for gaining improvements even though genetics probably are most important in terms of sprinting ability. There is a need of more studies were a higher extent of individualization is made

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 15 x 20 m for 100UNSUP and 30 x 20 m for 90SUP and 90UNSUP. Single-sprint performance (best time from 15 x 20 m sprints), repeated-sprint performance (mean time over 15 x 20 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

Intensity distribution for the sprint training groups during all training sessions.

<p>Best sprint from pre-training testing was set as reference (100%) for 90SUP and 90UNSUP, while best sprint within each training session was set as reference (100%) for 100UNSUP.</p

Between group changes (mean and 95% CIs) versus controls for underlying performance variables between pre- and post-training.

<p>The differences vs. control group are assessed by estimated marginal mean. Minus (-) indicates lower values post-training compared with the control group (assessed by estimated marginal means). HR = heart rate, BLa^- = blood lactate concentration, SL = step length, SR = step rate</p><p>* = significantly different (Bonferroni adjusted) from CON (<i>p</i> = 0.01).</p><p>Between group changes (mean and 95% CIs) versus controls for underlying performance variables between pre- and post-training.</p

Between-group changes (mean and 95% CIs) versus controls in physical performance from pre- to post-training.

<p>The differences vs. control group are assessed by estimated marginal mean. Minus (-) indicates lower values post-training</p><p>compared with the control group (assessed by estimated marginal means). CMJ = countermovement jump, Yo-Yo IR1 = Yo-Yo intermittent recovery level 1. No significant between-group differences were observed.</p><p>Between-group changes (mean and 95% CIs) versus controls in physical performance from pre- to post-training.</p

Physical and training characteristics at inclusion.

<p>Values are mean ± SD. BM = Body mass, Tot. vol. = Total training volume. Training values are based on self-reported weekly averages during the intervention period. There were no significant differences among the groups for any of the variables, except for body mass (*100UNSUP < 90UNSUP, <i>p</i> = 0.04).</p><p>Physical and training characteristics at inclusion.</p

Individual changes in 15x20 m mean sprint time from pre- to post-training tests.

<p>Individual changes in 15x20 m mean sprint time from pre- to post-training tests.</p

The effect of infliximab in patients with chronic low back pain and Modic changes (the BackToBasic study): study protocol of a randomized, double blind, placebo-controlled, multicenter trial

Low back pain is common and a significant number of patients experience chronic low back pain. Current treatment options offer small to moderate effects. Patients with vertebral bone marrow lesions visualized as Modic changes on magnetic resonance imaging may represent a subgroup within the low back pain population. There is evidence for inflammatory mediators being involved in development of Modic changes; hence, suppression of inflammation could be a treatment strategy for these patients. This study examines the effect of anti-inflammatory treatment with the TNF-α inhibitor infliximab in patients with chronic low back pain and Modic changes.Methods/design: The BackToBasic trial is a multicenter, double blind, randomized controlled trial conducted at six hospitals in Norway, comparing intravenous infusions with infliximab with placebo. One hundred twenty-six patients aged 18–65 with chronic low back pain and type 1 Modic changes will be recruited from secondary care outpatients’ clinics. The primary outcome is back pain-specific disability at day 154 (5 months). The study is designed to detect a difference in change of 10 (SD 18) in the Oswestry Disability Index at day 154/ 5 months. The study also aims to refine MRI-assessment, investigate safety and cost-effectiveness and explore the underlying biological mechanisms of Modic changes..Discussion: Finding treatments that target underlying mechanisms could pose new treatment options for patients with low back pain. Suppression of inflammation could be a treatment strategy for patients with low back pain and Modic changes. This paper presents the design of the BackToBasic study, where we will assess the effect of an anti-inflammatory treatment versus placebo in patients with chronic low back pain and type 1 Modic changes

The effect of infliximab in patients with chronic low back pain and Modic changes (the BackToBasic study): study protocol of a randomized, double blind, placebo-controlled, multicenter trial

Background Low back pain is common and a significant number of patients experience chronic low back pain. Current treatment options offer small to moderate effects. Patients with vertebral bone marrow lesions visualized as Modic changes on magnetic resonance imaging may represent a subgroup within the low back pain population. There is evidence for inflammatory mediators being involved in development of Modic changes; hence, suppression of inflammation could be a treatment strategy for these patients. This study examines the effect of anti-inflammatory treatment with the TNF-α inhibitor infliximab in patients with chronic low back pain and Modic changes. Methods/design The BackToBasic trial is a multicenter, double blind, randomized controlled trial conducted at six hospitals in Norway, comparing intravenous infusions with infliximab with placebo. One hundred twenty-six patients aged 18–65 with chronic low back pain and type 1 Modic changes will be recruited from secondary care outpatients’ clinics. The primary outcome is back pain-specific disability at day 154 (5 months). The study is designed to detect a difference in change of 10 (SD 18) in the Oswestry Disability Index at day 154/ 5 months. The study also aims to refine MRI-assessment, investigate safety and cost-effectiveness and explore the underlying biological mechanisms of Modic changes. Discussion Finding treatments that target underlying mechanisms could pose new treatment options for patients with low back pain. Suppression of inflammation could be a treatment strategy for patients with low back pain and Modic changes. This paper presents the design of the BackToBasic study, where we will assess the effect of an anti-inflammatory treatment versus placebo in patients with chronic low back pain and type 1 Modic changes