Michael Keiner

Michael Keiner
DHGS Deutsche Hochschule für Gesundheit und Sport · Department of Sport Science

PhD
Strength training to improve performance in sports

About

69
Publications
51,325
Reads
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786
Citations
Introduction
Keiner works on scientific questions concerning strength training in special populations (elite sports and youth sport). He is investigating the influence of long-term strength training interventions on strength and speed-strength strength performance.
Additional affiliations
October 2012 - March 2017
Swimming Federation of Lower Saxony
Position
  • Head of Department
Education
January 2010 - June 2015
Goethe-Universität Frankfurt am Main
Field of study
  • Training and Testing in Excercise

Publications

Publications (69)
Article
A basic question for many athletic coaches pertains to the maximum attainable strength level for youth athletes. The aim of this investigation was to establish reference values for the strength performance in the front and back squat in youth athletes. The strength performance in front and back squat of 141 elite youth soccer players was tested by...
Article
Full-text available
The requirement profiles of sports such as soccer, football, tennis and rugby demonstrate the importance of strength and speed-strength abilities, in addition to other conditional characteristics. During a game, these athletes complete a large number of strength and speed-strength actions. In addition to the linear sprint, athletes perform sprints...
Article
Full-text available
Objectives An early-established strength training regimen brings many benefit young athletes, especially those engaged in competitive sports. Strength training also leads to improve athletic performance, strength training is used for rehabilitation and injury prevention. The aim of this study was to evaluate how 2 years of additional strength trai...
Article
Full-text available
Abstract Objectives. - Strength and speed are 2 major factors that determine a swimmer’s sprint performance, especially swim sprint performance and swim starts. This study identified and examined variables that determine the influence of maximal strength performance on different swim performance styles and distances in trained adolescent swimmers....
Article
The current study aimed to compare the effects of plyometric and sprint vs. functional vs. strength training on linear sprint (LS 20 m), change of direction (COD; i.e., turning right and left), jump (squat jump [SJ]), and maximum strength (1 repetition maximum [1RM] for a quat) performance in elite adolescent soccer players. A longitudinal design w...
Poster
Full-text available
Unterschiede in den Korrelationsstärken zwischen isometrischen und dynamischen Kraftmessungen sowie Sprungleistungen bei Nachwuchsfußballern
Conference Paper
Einleitung Der Anstieg der Maximalkraft ist Ziel einer Vielzahl von Trainingsprogrammen in Prävention und Rehabilitation. Um Maximalkraft- und Muskeldickenzuwächse zu erzeugen, wird im Regelfall ein Krafttraining durchgeführt. Ergebnisse aus Tierstudien zeigen jedoch, dass auch langanhaltende Dehnungsspannungen zu signifikanten Muskelmasse- und Ma...
Article
Full-text available
Rebuilding strength capacity is of crucial importance in rehabilitation since significant atrophy due to immobilization after injury and/or surgery can be assumed. To increase maximal strength (MSt) strength training is commonly used. Literature from animal studies shows that long-lasting static stretching (LStr) interventions can also produce sign...
Article
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Previous research points out high relevance of maximal strength measurement in the diagnostics of different populations. However, there is inconsistency in procedures of maximum strength measurements. Thus, it must be questioned whether the results from different studies are actually comparable. Due to the aforementioned problems in standardization...
Article
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In basketball high intensity jumping and sprinting performance is of high importance. There seems to be a relationship between maximal strength (MSt) and jumping performance in general, but influence of MSt in the plantar flexors and jumping performance seems not to be investigated very well. Thus, the aim of this study was to investigate the influ...
Article
The sport of football cannot be represented holistically with a quantitative approach. The basis for this analysis was the construct of dynamic system theory. Based on the method of systematic game observation, a perturbation (= triggers that transfer a system into a state of instability) sign system was made, distinguishing between offensive (oP)...
Article
Full-text available
This study aims to analyze the influence of relative strength performance, determined by parallel back squats (REL SQ), on 30 m sprinting (LS) and on jumping performance (squat [SJ], countermovement [CMJ]) in a large sample (n = 492) of elite youth soccer players. The soccer players were divided into subgroups based on their strength performance: s...
Article
Full-text available
This narrative review deals with the topic of strength training in swimming, which has been a controversial issue for decades. It is not only about the importance for the performance at start, turn and swim speed, but also about the question of how to design a strength training program. Different approaches are discussed in the literature, with two...
Article
Full-text available
Options for monitoring sports have been continuously developed by using activity trackers to determine almost all vital and movement parameters. The aim of this study was to validate heart rate and distance measurements of two activity trackers and a cellphone app in a cross-sectional field study. Thirty-six moderate endurance-trained adults (20 ma...
Article
Full-text available
The aim of this investigation was to analyze significant differences in performance depending on the level of play (elite vs. amateur) in youth soccer players (under 17 years. old (U17) and U19). A cross-sectional study was conducted, and 45 elite and amateur male youth soccer players (16.56 +/- 0.9 years old) were evaluated in their performances i...
Article
Keiner, M, Wirth, K, Fuhrmann, S, Kunz, M, Hartmann, H, and Haff, GG. The influence of upper-and lower-body maximum strength on swim block start, turn, and overall swim performance in sprint swimming. J Strength Cond Res XX(X): 000-000, 2019-Maximum strength and speed strength are 2 major factors that determine a swimmer's performance, including sw...
Article
Full-text available
Background: Speed and strength performance have an essential role in soccer. It is well known there is a moderate to strong correlation between maximum strength, speed and jump performance. However most studies have analyzed only maximum strength values of the knee and hip extensors for the correlation analysis. Studies on the maximum strength of t...
Article
Die Durchführung eines Krafttrainings im Schwimmsport stellt ein seit Jahr-zehnten kontrovers diskutiertes Thema dar. Dabei geht es sowohl um die Be-deutung für die Leistung bei Start, Wenden und die Schwimmgeschwindigkeit, als auch um die Frage, wie ein Krafttraining zu gestalten ist. Unabhängig von der Leistungsentwicklung der Sportler, sollten a...
Article
Full-text available
Change of direction (COD) performance has an essential role in soccer. In the literature, there is a wide range of explained variance in correlation analyses between linearsprint performance, concentric power and maximum strength and COD performance. Therefore this study has (1) analyzed the influence of linear-sprint performance, concentric power...
Article
Water polo is a multifaceted sport that is characterized by explosive actions, including sprint swimming, jumping, throwing, and struggling against opponents. Based upon these factors, maximal and speed strength may be important characteristics to develop in water polo players. However, more research is needed to further understand the relationship...
Poster
Full-text available
Background: The possibilities of continuously monitoring ever yday training have become more varied and precise. Fitness trackers are common dev ices used for collecting training data. The aim of this study was to validate the optical heart rate (HR) and GPS distance measurements under real conditions. Methods: In total, 30 moderate endurance-trai...
Conference Paper
Schlüsselwörter: Psychische Erkrankungen, Bewegungssetting, qualitative Forschung Einleitung Menschen mit psychischen Erkrankungen sind einem erhöhten Gesundheitsrisiko ausge-setzt. Durch regelmäßige Bewegung kann dieses Risiko reduziert werden, da sich Bewe-gung positiv auf die körperliche und psychische Gesundheit auswirkt (Rosenbaum, Tiedemann,...
Article
Full-text available
The possibilities of continuously monitoring everyday training have become more varied and precise. Fitness trackers are common devices used for collecting training data. The aim of this study was to validate the optical heart rate (HR) and global positioning system (GPS) distance measurements under real conditions. In total, 30 moderate endurance-...
Article
Full-text available
Introduction: The possibilities of continuously monitoring everyday training have become more varied and precise. Fitness trackers are common devices used for collecting training data. The aim of this study was to validate the optical heart rate (HR) and GPS distance measurements under real conditions. Methods: Thirty moderate endurance-trained adu...
Article
Full-text available
Change of direction (COD) is a performance limiting factor in team sports. However, there are no exact definitions of which physical abilities limit the COD performance. Nevertheless, different methods are used or are recommended as equally effective in professional practices to measure COD performance. Therefore, the aim of this study is to evalua...
Article
Rule 40 der Olympic Charta reguliert den Umgang mit Partnern und Sponsoren während des Zeitraums Olympischer Spiele. Hiermit wird mit Ausnahme der offiziellen Olympischen Sponsoren jegliche Art von Bezugnahme zwischen Athleten und Unternehmen bzw. Partnern unterbunden. Hintergrund der Regel ist zum einen, die offiziellen IOC-Sponsoren zu schützen....
Article
Full-text available
This study was designed to evaluate the effects of long-term (2 years) strength training on reactive strength. To control the effect of the strength training intervention, reference data in trained and untrained adolescents were determined. Therefore, part 1 of this investigation evaluated a cross-sectional analysis of untrained adolescents (studen...
Article
Full-text available
Over the last two decades, exercise of the core muscles has gained major interest in professional sports. Research has focused on injury prevention and increasing athletic performance. We analyzed the guidelines for so-called functional strength training for back pain prevention and found that programs were similar to those for back pain rehabilita...
Article
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The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodiz...
Article
Despite the common use of jogging strollers, only a few studies cover their influence on running patterns. Kinematic studies have shown differences in the upper body movement, while potential changes in plantar pressure remain unclear. Therefore, 30 healthy sport students were asked to run at a self-selected speed with and without a jogging strolle...
Article
Full-text available
For the development of speed strength in professional sports, “specific” strength training in the half or the quarter squat have been recommended. Due to the better lever ratios, higher loads have to be used to induce the necessary training stimuli compared to the deep squat. Therefore, intradiscal pressure and compressive forces on vertebral bodie...
Article
Full-text available
Strength training-induced increases in speed-strength seem indisputable. For trainers and athletes the most efficient exercise selection in the phase of preparation is of interest. Therefore, this study determined how the selection of training exercise influences the development of speed-strength and maximal strength during an 8-week training inter...
Article
Full-text available
The purpose of this study was to establish whether physical attributes can differentiate between professional, amateur and elite youth soccer players; such a distinction could aid in the selection process for youth soccer. Therefore, this investigation evaluated a suspected difference in the performance tests of the slow and fast stretch and the sh...
Article
Full-text available
The training of the trunk muscles has become a standard practice for improving strength and speed-strength and reducing one’s susceptibility to injury. Athletic movements, such as sprints, lead to high forces acting on the torso and hips. The trunk muscles must control the extremities and transfer these forces so that efficient locomotion is ensure...
Article
Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant d...
Article
The aim of this investigation was to analyze the effects of an eccentric strength training protocol using supramaximal loads (> 1RM; 1RM = one-repetition maximum) on different maximal and explosive strength parameters of the lower extremity. The eccentric maximal strength (EX max), maximal isometric strength (MVC = "maximal voluntary contraction"),...
Article
Full-text available
For track, field and team sports, many authors advise sport-specific strength training with half and quarter squats instead of parallel squats. Due to the sport-specific argument, higher correlations with sprint performance could be expected for half and quarter squats. Hence, correlations between sprint performance (30 m linear sprint) and both On...
Thesis
Full-text available
Das Anforderungsprofil des Fußballspieles zeigt, dass Maximal- und Schnellkraftleis-tungen einen leistungsdeterminierenden Faktor in dieser Sportart einnehmen. Krafttrai-ningsinterventionen im Kindes- und Jugendalter bis hin zum Erwachsenenalter führen zu Leistungsverbesserungen in Maximal- und Schnellkraftparametern. Ziel dieser Untersuchung ist e...
Article
Full-text available
The aim of the study was the evaluation of the correlation between maximal strength and muscle mass depending on the kind of analysis which was used. Two different methods of strength evaluation and several morphological parameters were used. 77 male participants (age: 27,2 ± 6,6 years; body height: 179,9 ± 4,0 cm; body weight: 82,5 ± 10,4 kg) join...
Article
The aim of the study was the evaluation of the correlation between maximal strength and muscle mass depending on the kind of analysis which was used. Two different methods of strength evaluation and several morphological parameters were used. 77 male participants (age: 27,2 ± 6,6 years; body height: 179,9 ± 4,0 cm; body weight: 82,5 ± 10,4 kg) join...
Article
Full-text available
Abstract In soccer, strength, power and speed are very important because of the large number of power actions performed during the game. Therefore, the aim of this study was to examine the influence of periodised strength training for power performance more than 2 years. In this study, 134 elite youth soccer players were recruited from two youth tr...
Article
Training and activity level are important predictors of motor development. At present, many children and adolescents do not participate in any sport activity in their leisure time.In this investigation, we analyzed the level of performance of the stretch and shortening cycle in childhood and youth. Data of 801 participants were recorded for two sep...
Article
Full-text available
The process of warming up prepares athletes for subsequent stress and increases their level of performance. Functional exercises are often included in warm-up programs for power sports, although a positive effect of functional exercises has not been confirmed. The aim of this study was to measure a possible effect on sprint performance of functiona...
Article
Kraft und Schnellkraftleistungen stellen, neben anderen konditionellen Anforderungen, bzw. technischen, taktischen und psychischen Anforderungen in vielen Mannschaftssportarten einen leistungsdeterminierenden Faktor dar. Die Maximalkraft wird dabei als die höchste Kraft verstanden, die das neuromuskuläre System bei einer maximalen willkürlichen Kon...
Article
Full-text available
Aufgrund des Anforderungsprofils im Fußball sind Kraft- und Schnellkraftfähigkeit von hoher Bedeutung. Um einen Leistungsvorteil zu generieren, ist die Ausprägung der Komponente Kraft als sinnvoll zu erachten. In dieser Untersuchung wurde der Einfluss eines einjährigen Krafttrainings auf die Sprintleistung über eine Distanz von 30 Metern bei jugend...
Article
Zusammenfassung Die Maximalkraft gilt in den meisten Spielsportarten als Grundlage für ein hohes Leistungsniveau. Unter Maximalkraft wird die höchste Kraft verstanden, die das neuromuskuläre System in einer maximal willkürlichen Kontraktion erzeugen kann. In der vorliegenden Untersuchung wurde die Leistungsfähigkeit der Maximalkraft von jugendliche...
Article
Summary Functional training and specific strength training are widely used terms. In the last two decades a lot of strength training interventions were named functional of specific in the field of fitness training and competitive sports. This occurred without any substantive reason beside the argument that the interventions are kinematically and ki...
Article
Strength and power are next to the other conditional requirements, as well as the technical, tactical, psychological requirements, a limiting factor in team sports. Therefore, it makes sense to also train strength. The maximal strength is understood as the maximal force the neuromuscular system can produce during a maximal voluntary contraction. A...
Article
In many team sports maximum strength is the basis for a high performance level. Maximum strength is understood as the maximal force the neuromuscular system can produce during a maximal voluntary contraction. In this investigation, the strength performance of elite youth soccer players (n = 135) with and without experience in strength training was...
Article
In this investigation, the stretch-shortening cycle (SSC) performance of untrained male children and juveniles was measured and compared to that of soccer-playing children of equivalent age. Te subjects were between 9 and 18 years old. Five age cohorts were formed. Every cohort consisted of two adjacent ages. Te groups including the soccer-playing...

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Projects (2)
Project
1. Introduction 2. Adaptation * satellite cells * increased number of myofibers * adaptation potential of different fiber types * increased cross-sectional area through hyperplasia ? 3. Initiating stimulus * mechanical stimulus application (incl. mechano-sensitive signal pathways) * metabolic stress / hormones * methodological problems 4. training recommendations
Project
Narrative review article Definition and classification of the short- and long SSC Proposed mechanisms of the performance potentiation of the SSC Influencing neuronal factors Influencing morphological factors Problem of the reflex-induced performance-potentiation in the long SSC Abstract and reference list will follow soon