Latest research in football - week 5 - 2016

As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases.

Following studies were retrieved for this week:

#1 The Effects of in-Season Repeated Sprint Training Compared to Regular Soccer Training
Reference: J Hum Kinet. 2015 Dec 30;49:237-44. doi: 10.1515/hukin-2015-0126. eCollection 2015.
Authors: Nedrehagen ES, Saeterbakken AH
Download link:
Summary: The aim of this study was to compare the effects of repeated sprints (RSA) training and regular soccer training on Yo-Yo IR-1 and RSA performance (6 x 40 m shuttle sprints). Thirteen semi-professional female soccer players and nine amateur male soccer players were randomised into a repeated sprint group (RSG; n = 12) or a regular soccer training group (STG; n = 10). The RSG soccer players executed 3-4 sets of 4-6 repeated sprints (30 m with 180° directional changes) weekly during the last eight weeks of the in-season. In parallel, the STG soccer players performed low- to moderate intensity soccer training in form of technical or tactical skills. The RSG showed 15% improvement in Yo-Yo IR-1 (p = 0.04; ES = 1.83) and their mean RSA times were reduced by 1.5% (p = 0.02; ES = 0.89). No significant changes were found for the STG (Yo-Yo IR-1, p = 0.13; RSA, p = 0.49). Comparing the groups, greater improvements were observed in Yo-Yo IR-1 for the RSG (p = 0.02; ES = 1.15), but not for the RSA (p = 0.23; ES = -0.33). Similar training volumes and intensities (% of HFmax) were observed between the groups (p = 0.22 and p = 0.79). In conclusion, a weekly RSA session integrated into a regular soccer regime improved in-season RSA and Yo-Yo IR-1 performance compared to regular soccer training.

#2 Effect of the Game Design, the Goal Type and the Number of Players on Intensity of Play in Small-Sided Soccer Games in Youth Elite Players
Reference: J Hum Kinet. 2015 Dec 30;49:229-35. doi: 10.1515/hukin-2015-0125. eCollection 2015.
Authors: González-Rodenas J, Calabuig F, Aranda R
Download link:
Summary: The aim of this study was to compare the effects of game design modification, the type of the goal and the number of players on the intensity of play in small-sided soccer games (SSGs) in youth elite players. Twenty young soccer players (age 13.7 ± 0.5 years, body mass 57.4 ± 7.8 kg, body height 1.67 ± 7.8 m, maximal heart rate 201.1 ± 8.2 beats/min) performed three types of SSGs (possession play (PP) vs. regular goals (RG) vs. small goals (SG)) in both four-a-side and six-a-side formats. The heart rate responses were recorded and analysed as an indicator of the intensity of play. The four-a-side format obtained higher intensity of play than six-a-side for PP (p<0.05), but not for SG and RG. SG showed higher intensity of play than RG for four-a-side (p<0.001), but not for six-a-side. PP registered higher intensity of play than RG (p<0.05), but not than SG in four-a-side, whereas in six-a-side no differences were found between the three formats. In conclusion, the modification of variables such as the number of players, the game design and the type of the goal influences the intensity of play in small-sided soccer games in youth players.

#3 The angle-torque-relationship of the subtalar pronators and supinators in male athletes: A comparative study of soccer and handball players
Reference: Technol Health Care. 2016 Jan 21. [Epub ahead of print]
Authors: Hagen M, Asholt J, Lemke M, Lahner M
Summary: It is currently unclear how participation in different sports affects the angle-specific subtalar pronator and supinator muscle strength and pronator-to-supinator strength ratio (PSR). Based on the hypothesis that both differences sport-related patterns of play and foot-ground interaction may lead to sport-specific muscle adaptations, this study compared the angle specific pronator and supinator strength capacity of handball and soccer players. Eighteen healthy male handball and 19 soccer players performed maximum isometric voluntary isometric contractions using a custom-made testing apparatus. Peak pronator (PPT) and supinator torques (PST), pronator and supinator strength curves (normalised to the peak torque across all joint angles) and PSR were measured in five anatomical joint angles across the active subtalar range of motion (ROM). All analysed parameters were dependent on the subtalar joint angle. The ANOVA revealed significant `joint angle' × `group' interactions on PPT, pronator strength curves and PSR. No group differences were found for active subtalar ROM. In previously uninjured handball and soccer athletes, there were intrinsic differences in angle-specific subtalar pronator muscle strength. The lower PSR, which was found in the most supinated angle, can be seen as a risk factor for sustaining an ankle sprain.

#4 Effect of Kinesiotape Applications on Ball Velocity and Accuracy in Amateur Soccer and Handball
Reference: J Hum Kinet. 2015 Dec 30;49:119-29. doi: 10.1515/hukin-2015-0114. eCollection 2015.
Authors: Müller C, Brandes M
Download link:
Summary: Evidence supporting performance enhancing effects of kinesiotape in sports is missing. The aims of this study were to evaluate effects of kinesiotape applications with regard to shooting and throwing performance in 26 amateur soccer and 32 handball players, and to further investigate if these effects were influenced by the players' level of performance. Ball speed as the primary outcome and accuracy of soccer kicks and handball throws were analyzed with and without kinesiotape by means of radar units and video recordings. The application of kinesiotapes significantly increased ball speed in soccer by 1.4 km/h (p=0.047) and accuracy with a lesser distance from the target by -6.9 cm (p=0.039). Ball velocity in handball throws also significantly increased by 1.2 km/h (p=0.013), while accuracy was deteriorated with a greater distance from the target by 3.4 cm (p=0.005). Larger effects with respect to ball speed were found in players with a lower performance level in kicking (1.7 km/h, p=0.028) and throwing (1.8 km/h, p=0.001) compared with higher level soccer and handball players (1.2 km/h, p=0.346 and 0.5 km/h, p=0.511, respectively). In conclusion, the applications of kinesiotape used in this study might have beneficial effects on performance in amateur soccer, but the gain in ball speed in handball is counteracted by a significant deterioration of accuracy. Subgroup analyses indicate that kinesiotape may yield larger effects on ball velocity in athletes with lower kicking and throwing skills.

#5 Epidemiology of injuries sustained by players during the 16th Under-17 South American Soccer Championship
Reference: Rev Esp Cir Ortop Traumatol. 2016 Jan 30. pii: S1888-4415(15)00165-4. doi: 10.1016/j.recot.2015.12.002. [Epub ahead of print] [Article in English, Spanish]
Authors: Pangrazio O, Forriol F
Summary: We performed an epidemiological study of the traumatic injuries during the XVI South American U-17 Football Championship, 2015. Observational surveys submitted by the 10 teams medical services of 220 players were used and thirty-five games were held and 116 goals (3.31 per game) were recorded. 103 lesions, ie, 2.94 per game or 32.7 injuries per 1,000 min were recorded. Fifty-six were from direct contact and 66 requiring treatment. 36% of the injuries were punished by fault and 26% of the injuries also saw card. Injuries were most common in the ankle (15 cases), Achilles tendon (14 cases) and thigh (14 cases), followed by trauma to the knee and foot (7 cases each), face and the lumbar region (6 cases each), being rare in the upper extremity. Injuries during Soccer World Cup are difficult to predict and prevent, but serious injuries are rare. Is necessary to establish protocols that get adequate health care at all levels to solve problems produce, both in training and during the competition, and be prepared to solve the serious problems that may arise.

#6 Feasibility of Using Soccer and Job Training to Prevent Drug Abuse and HIV
Reference: AIDS Behav. 2016 Feb 2. [Epub ahead of print]
Authors: Rotheram-Borus MJ, Tomlinson M, Durkin A, Baird K, DeCelles J, Swendeman D
Summary: Many young, South African men use alcohol and drugs and have multiple partners, but avoid health care settings-the primary site for delivery of HIV intervention activities. To identify the feasibility of engaging men in HIV testing and reducing substance use with soccer and vocational training programs. In two Cape Town neighborhoods, all unemployed men aged 18-25 years were recruited and randomized by neighborhood to: (1) an immediate intervention condition with access to a soccer program, random rapid diagnostic tests (RDT) for alcohol and drug use, and an opportunity to enter a vocational training program (n = 72); or (2) a delayed control condition (n = 70). Young men were assessed at baseline and 6 months later by an independent team. Almost all young men in the two neighborhoods participated (98 %); 85 % attended at least one practice (M = 42.3, SD = 34.4); 71 % typically attended practice. Access to job training was provided to the 35 young men with the most on-time arrivals at practice, drug-free RDT, and no red cards for violence. The percentage of young men agreeing to complete RDT at soccer increased significantly over time; RDTs with evidence of alcohol and drug use decreased over time. At the pre-post assessments, the frequency of substance use decreased; and employment and income increased in the immediate condition compared to the delayed condition. HIV testing rates, health care contacts, sexual behaviors, HIV knowledge, condom use and attitudes towards women were similar over time. Alternative engagement strategies are critical pathways to prevent HIV among young men. This feasibility study shows that soccer and job training offer such an alternative, and suggest that a more robust evaluation of this intervention strategy be pursued.

#7 Hand Grip Strength Vs. Sprint Effectiveness in Amputee Soccer Players
Reference: J Hum Kinet. 2015 Jan 12;48:133-9. doi: 10.1515/hukin-2015-0099. eCollection 2015.
Authors: Wieczorek M, Wiliński W, Struzik A, Rokita A
Download link:
Summary: Amputee soccer is one of the types of soccer designed for the disabled, especially those who have undergone amputations, as well as those with extremity dysfunction. The objective of the study was to find the relationship between hand grip strength and sprint time in amputee soccer players. Thirteen field amputee soccer players participated in the study. A SAEHAN hydraulic hand dynamometer manufactured by Jamar was used for hand grip strength measurements. The sprint running test was conducted over a distance of 30 m. The Fusion Smart Speed System was employed for running time measurements. No statistically significant relationships were found between hand grip strength of the left or right hand, and sprint times over 1, 5, 10, 15, 20, 25 and 30 m. Analysis of the running velocity curve of the subjects showed an interesting profile characterized by a 15 meter-long acceleration phase and a significant velocity increase over a distance of 20 - 25 m. The study suggests that there is no relationship between hand grip strength and sprint effectiveness in amputee soccer players. The specificity of locomotion with the use of elbow crutches among elite Polish amputee soccer players probably accounts for the profile of the sprint velocity curve. Extension of the acceleration phase in the sprint run and a velocity increase in the subsequent part of the run were observed.

#8 Is Heading in Youth Soccer Dangerous Play?
Reference: Phys Sportsmed. 2016 Feb 1. [Epub ahead of print]
Authors: O'Kane JW
Summary: Soccer is among the most popular youth sports with over 3 million youth players registered in the U.S. Soccer is unique in that players intentionally use their head to strike the ball, leading to concerns that heading could cause acute or chronic brain injury, especially in the immature brains of children. Pub Med search without date restriction was conducted in November 2014 and August 2015 using the terms soccer and concussion, heading and concussion, and youth soccer and concussion. 310 articles were identified and reviewed for applicable content specifically relating to youth athletes, heading, and/or acute or chronic brain injury from soccer. Soccer is a low-risk sport for catastrophic head injury, but concussions are relatively common and heading often plays a role. At all levels of play, concussions are more likely to occur in the act of heading than with other facets of the game. While concussion from heading the ball without other contact to the head appears rare in adult players, some data suggests children are more susceptible to concussion from heading primarily in game situations. Contributing factors include biomechanical forces, less developed technique, and the immature brain's susceptibility to injury. There is no evidence that heading in youth soccer causes any permanent brain injury and there is limited evidence that heading in youth soccer can cause concussion. A reasonable approach based on U.S. Youth Soccer recommendations is to teach heading after age 10 in controlled settings, and heading in games should be delayed until skill acquisition and physical maturity allow the youth player to head correctly with confidence.

#9 A comparison of athletic movement between talent identified juniors from different football codes in Australia: Implications for talent development
Reference: J Strength Cond Res. 2016 Jan 29. [Epub ahead of print]
Authors: Woods T C, Keller S B, McKeown I, Robertson S
Summary: This studied aimed to compare the athletic movement skill of talent identified (TID) junior Australian Rules football (ARF) and soccer players. The athletic movement skill of 17 TID junior ARF players (17.5 - 18.3 y) was compared against 17 TID junior soccer players (17.9 - 18.7 y). Players in both groups were members of an elite junior talent development program within their respective football codes. All players performed an athletic movement assessment that included an overhead squat, double lunge, single leg Romanian deadlift (both movements performed on right and left legs), a push up and a chin up. Each movement was scored across three essential assessment criteria using a three point scale. Total score for each movement (maximum of nine) and overall total score (maximum of 63) were used as the criterion variables for analysis. A multivariate analysis of variance (MANOVA) tested the main effect of football code (two levels) on the criterion variables, whilst a one-way ANOVA identified where differences occurred. A significant effect was noted, with the TID junior ARF players outscoring their soccer counterparts when performing the overhead squat and push up. No other criterions significantly differed according to the main effect. Practitioners should be aware that specific sporting requirements may incur slight differences in athletic movement skill between TID juniors from different football codes. However, given the low athletic movement skill noted in both football codes, developmental coaches should address the underlying movement skill capabilities of juniors when prescribing physical training in both codes.

The Training Manager -