| 1. |
- Augustsson, Jesper, Docent, 1964-, et al.
(författare)
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Development of a Novel Nordic Hamstring Exercise Performance Test Device : A Reliability and Intervention Study
- 2022
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Ingår i: Sports. - : MDPI. - 2075-4663. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- There is evidence that a knee flexor exercise, the Nordic hamstring exercise (NHE), prevents hamstring injuries. The purpose of this study was therefore to develop, and to determine the reliability of, a novel NHE test device and, further, to determine the effectiveness of a 10-week low volume NHE program on NHE performance. Twenty female football (soccer) players, aged 16–30 years, participated in this study. From a kneeling position on the device, with the ankles secured under a heavy lifting sling, participants leaned forward in a controlled manner as far as possible (eccentric phase) and then returned to the starting position (concentric phase). A tape measure documented the forward distance achieved by the participants in cm. Participants completed three separate occasions to evaluate test-retest reliability. Additionally, 14 players performed a low volume (1 set of 5 repetitions) NHE program once weekly for 10 weeks. No significant test-retest differences in NHE performance were observed. The intra-class correlation coefficient was 0.95 and the coefficient of variation was 3.54% between tests. Mean improvement in the NHE performance test by the players following training was 22% (8.7 cm), p = 0.005. Our test device reliably measured NHE performance and is easy to perform in any setting. Further, NHE performance was improved by a 10-week low volume NHE program. This suggests that even a small dose (1 set of 5 repetitions once weekly) of the NHE may enhance NHE performance.
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| 2. |
- Gerdin, Göran, 1980-, et al.
(författare)
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Relative Age Effect in Swedish Male and Female Tennis Players Born in 1998–2001
- 2018
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Ingår i: Sports. - Basel : MDPI. - 2075-4663. ; 6:2, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The relative age effect (RAE) has been extensively debated and researched in both popularmedia and academic discourse. This study examined RAE in Swedish tennis players born in1998–2001. The study was conducted in 2015–2016 and includes all ranked Swedish tennis players(n = 1835) registered in the Swedish Tennis Association database from the year 2014. The resultsshow that when the birth dates of the corresponding Swedish population and all the ranked playersare compared, they show a moderate RAE; however, the higher up they are in the ranking system,the greater the RAE becomes. Top 10 players display an average of 64.1% being born in the firsthalf of the year. Some gender differences were also found, with a greater proportion of bothhigher and lower ranked females being born in the first half of the year. In our discussion ofthe findings we raise several issues that need to be addressed to provide more equal opportunitiesfor all junior players regardless of birth date. Resolving ongoing problems associated with RAEin competitive sports such as tennis is important both in term of prolonged participation in thesport and increased performance. Suggestions made in this article include recognising RAE whendesigning the format of competitions/tournaments, not using official rankings until the juniorsget older, addressing RAE in a “gender sensitive” way, and conducting further in-depth studiesin which RAE is understood/examined as being associated with environmental factors. Althoughthese findings show the RAE effect in Swedish tennis players, thus pointing at the need for furtherconsideration in terms of ranking and selection procedures to ensure equal opportunities for playerdevelopment, the study also concludes by reasserting an emphasis on a holistic approach to playerdevelopment in which coaches focus on the developmentally appropriate needs and potential of eachindividual player regardless of their biological age.
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| 3. |
- Augustsson, Jesper, Docent, 1964-, et al.
(författare)
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An Assessment of the Ratio between Upper Body Push and Pull Strength in Female and Male Elite Swedish Track and Field Throwers
- 2024
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Ingår i: Sports. - : MDPI. - 2075-4663. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- Data on the strength ratio between agonist and antagonist muscles are frequently examined in sports testing, given its correlation with athletic performance. The purpose of this study was to determine the agonist-to-antagonist ratio of upper body strength in female and male elite Swedish track and field throwers using a new push (bench press) and pull (supine bench row) test device, and to determine its reliability. The study involved eight female and nine male athletes, aged 19–29 years, engaging, respectively, in discus, hammer, and shot put competitions at both national and international levels. The athletes’ maximum isometric force was assessed during the bench press (push) and supine bench row (pull) exercises, respectively, using a custom-built test device. The test–retest reliability of the device was also examined. The total push-to-pull strength ratio for the female throwers was 1.15, whereas male throwers demonstrated a ratio of 1.22. Total push and pull force for the female throwers was significantly less than for the male throwers (5511 N vs. 8970 N, p < 0.001). Intraclass correlation coefficients ranged from 0.93 to 0.96 for the bench press and supine bench row exercise, indicating that the push and pull test device was highly reliable. The main findings of this study were that elite female and male discus, hammer, and shot put throwers exhibited 15% and 22% more pushing (bench press) than pulling (supine bench row) strength. Push and pull strength in the female throwers ranged from 47% to 71% of that of the male throwers. The push and pull test device is a reliable tool in establishing the agonist-to-antagonist ratio of upper body strength of athletes. Coaches and athletes may benefit from examining upper body push and pull strength ratios for training planning and prescription.
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| 4. |
- Augustsson, Jesper, Docent, 1964-, et al.
(författare)
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Differences in Peak Knee Flexor Force between Eccentric-Only and Combined Eccentric-Concentric Nordic Hamstring Exercise
- 2023
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Ingår i: Sports. - : MDPI. - 2075-4663. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- In many sports, the hamstring strain injury is a common injury. There is evidence that the Nordic hamstring exercise (NHE), a knee flexor exercise, can reduce hamstring injury risk in athletes. In research on hamstring injury prevention, eccentric-only NHE is typically performed, whereas in sports, it is relatively common for athletes to perform NHE eccentrically-concentrically. Further, NHE strength is generally assessed by measuring knee flexor force through an ankle brace, attached atop of a load cell. An alternative method might be to assess knee flexor force about the knee joint using a force plate. The aim of the study was to investigate differences in peak knee flexor force between eccentric-only and combined eccentric-concentric NHE. The purpose was also to determine the correlation between hamstring force measured at the ankle using a load cell (current gold standard) and force assessed about the knee joint using a force plate during NHE. Fifteen junior and senior elite soccer and track and field athletes (3 women and 12 men aged 17–27 years) performed eccentric NHE (ENHE) in which they leaned forward as far as possible until breakpoint and eccentric-concentric NHE (ECNHE) where they returned to the starting position. A linear encoder measured the position at which peak force occurred during the NHEs. Force assessed at the ankle differed significantly (678 vs. 600 N, p < 0.05), whereas force about the knee joint did not (640 vs. 607 N, p > 0.05) between ENHE and ECNHE (12 and 5% difference, respectively). The forward distance achieved by the participants in cm at breakpoint for ENHE was 37% higher than at the coupling phase for ECNHE (74 vs. 54 cm, p < 0.001). Very strong significant (p < 0.01) correlations were noted between peak force assessed at the ankle and about the knee joint for ENHE and ECNHE, r = 0.96 and r = 0.99, respectively. Our results suggest that ECNHE, where peak knee flexor force was reached with 37% less forward movement, may complement ENHE, i.e., during hamstring injury rehabilitation, where a position of great knee extension may not be well tolerated by the athlete. Further, assessing knee flexor force about the knee joint using a force plate may provide an alternative to measuring force at the ankle using a load cell when testing NHE strength.
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| 5. |
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| 6. |
- Augustsson, Jesper, Docent, 1964-, et al.
(författare)
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Speed Matters in Nordic Hamstring Exercise : Higher Peak Knee Flexor Force during Fast Stretch-Shortening Variant Compared to Standard Slow Eccentric Execution in Elite Athletes
- 2023
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Ingår i: Sports. - : MDPI. - 2075-4663. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Hamstring strain injuries are prevalent in many sports. Research has demonstrated that the Nordic hamstring exercise (NHE), a knee-dominant exercise addressing the posterior chain muscles, can aid in reducing the risk of hamstring injuries in athletes. However, most research on hamstring injury prevention has focused on performing the eccentric version of the NHE (NHEECC). In contrast, in sports, it is quite frequent for athletes to use an eccentric–concentric version of the NHE. Additionally, eccentric NHE is typically performed using a slow, controlled tempo. The effect of a fast stretch-shortening cycle NHE (NHESSC) compared to standard slow NHEECC on peak knee flexor force has not been investigated. The aim of the study was therefore to investigate fast NHESSC vs. standard slow NHEECC. Our hypothesis posited that peak knee flexor force would be greater for fast NHESSC compared with standard slow NHEECC. The study involved 22 elite athletes (actively competing in both national and international events) consisting of female (n = 10) and male (n = 7) track and field athletes and male football players (n = 5), aged 17–31 years. The participants performed maximum trials of slow NHEECC and fast NHESSC repetitions in which measurement of bilateral peak knee flexor force was conducted at the ankle with the use of a load cell. During the NHEs, a linear encoder was used to measure both the position where the peak knee flexor force was recorded and the average eccentric velocity. SSC contributed to an enhanced NHE performance, where bilateral absolute peak knee flexor force was 13% higher for fast NHESSC vs. standard slow NHEECC (822 vs. 726 N, p < 0.01, ES = 0.54). Participants achieved a 32% greater forward distance at the breakpoint stage during NHEECC compared to the coupling phase for NHESSC (54 vs. 41 cm, p < 0.001, ES = 1.37). Eccentric average velocity was more than three times higher for NHESSC compared with NHEECC (0.38 vs. 0.12 m/s, p < 0.001, ES = 3.25). The key findings of this study were that SSC contributed to an enhanced NHE performance, where absolute peak knee flexor force was 13% greater for fast NHESSC compared to standard slow NHEECC. The fast NHESSC could therefore be an interesting alternative to the standard slow NHEECC execution, as it may offer potential advantages for sprint performance, as well as hamstring injury prevention and rehabilitation.
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| 7. |
- Ryman Augustsson, Sofia, et al.
(författare)
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Changes in Physical Fitness in Youth Padel Players during One Season : A Cohort Study
- 2024
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Ingår i: Sports. - Basel : MDPI. - 2075-4663. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate how physical fitness performance, which is related to the strength and power of the lower extremities and core, as well as lateral agility, changes across 20 weeks of in-season training in youth female and male padel players. This study was conducted using a prospective cohort design on 16 Swedish high school padel players aged between 15 and 18 years old. The players were assessed at baseline with five tests of their physical fitness and followed prospectively, with the registration of their training load for 20 weeks, and then assessed at a follow-up, approximately five months later. The players increased their performance in all tests (p ≤ 0.02). The mean improvement in their Isometric squat test performance was 20% for peak force, 18% for relative strength value and 69% for average rate of force development. Their improvement in the squat jump test performance was 9%, whereas the improvement in their countermovement jump test was 6%. For the 30 second sit-up test, an improvement of 14% was observed. Improvements were also noted for the 30 second side hop test performance on both the right (9%) and left leg (11%). The effect size ranged from 0.31 to 1, respectively, for the tests, representing a small to large effect. The data from this study suggest that an improvement in physical fitness performance can be obtained during 20 weeks of padel training. © 2024 by the authors.
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| 8. |
- Ryman Augustsson, Sofia, et al.
(författare)
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The significance of maximal squat strength for neuromuscular control in elite handball players : a cross-sectional study
- 2023
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Ingår i: Sports. - : MDPI. - 2075-4663. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- Both weak muscle strength and impaired neuromuscular control has previous been suggested as risk factors for future traumatic knee injury. However, data on the relationship between these two factors are scarce. Thus, the aim of this study was to investigate the relationship and influence of the one repetition maximum (1RM) barbell squat strength on dynamic knee valgus in elite female and male handball players. In this cross-sectional study 22 elite handball players (7 females) were included. A unilateral drop jump (VDJ) test was used for the assessment of frontal plane dynamic knee valgus. Players also performed a one repetition maximum (1RM) barbell squat test, expressed relative to bodyweight (r1RM), to assess maximal strength, which were dichotomized to analyze ‘weak’ versus ‘strong’ players according to median. Correlations were noted between r1RM in squat and knee valgus angle for both the non-dominant (r = −0.54; p = 0.009) and dominant leg (r = −0.46, p = 0.03). The odds of knee valgus were eight times higher, for the dominant leg, in the weak group compared to the strong group (p = 0.03) and 27 times higher, for the non-dominant leg (p = 0.002). The outcome of the present study suggests that maximum squat strength plays an important role when it comes to neuromuscular control of the knee, and that weak handball players are at higher risk of knee valgus compared to strong players during jumping activity.
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