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.

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. 

Background

Maximum-strength tests are commonly used to detect muscle weakness in persons with cerebral palsy (CP). Tests of explosive strength (power) in the lower extremities, such as vertical jump tests, are more uncommon but might supplement maximum-strength testing by providing additional information about motor function.Research questionIs it feasible and useful to measure single-leg vertical jumping in young adults with CP?

Methods

Eleven persons with spastic CP (18–30 years), able to walk without support, were compared with a reference group. Jump height and power generation in jumping were measured using a 3D motion-analysis system and force plates. Maximum strength in plantarflexors was measured on the same occasion. Data were analysed using non-parametric statistics.

Results

Jump height was significantly greater in the reference group than in the group with CP, both relative to the less-involved leg of the participants with CP (p = .007) and relative to their more-involved leg (p < .001). In the group with CP, jump height was twice as great for the less-involved leg than for the more-involved leg (p = .008). Power generation at the hip joint was similar between the groups but differed for the knee and ankle joints (p = .001–.033). In the reference group, most of the power was generated at the ankle joint, while the hip was the dominant power generator for the more-involved leg in the group with CP.

Muscle strength in the group with CP showed a high correlation with jump height (rho = .745, p < .001) and power generation at the ankle (rho = .780, p = .001).

Significance

The single-leg vertical jump test proved capable of measuring jump height and power generation in participants with CP. It also identified explosive muscle weakness both relative to a reference group and between legs. Hence the jump test may provide information additional to common tests of maximal muscle strength in persons with CP.

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.

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.

PurposeThe purpose of this study was to study dynamic hip external rotation strength in patients with Femoroacetabular impingement surgery (FAI) syndrome who have undergone unilateral arthroscopic treatment and returned to sports.

MethodsA cross-sectional study was performed using an observational group (n = 22) and a matched control group (n = 22). Dynamic external rotation strength of the hip was measured using the Augustsson Strength Test, which has shown high reliability for examining side-to-side differences in hip muscle strength.

ResultsDynamic hip external rotation strength was significantly lower in the arthroscopically treated hip compared with the non-treated hip within the observational group (p < 0.004).

ConclusionThis cross-sectional study shows that at return to sports, patients who have undergone unilateral arthroscopic treatment for FAI syndrome do not have adequate hip muscle strength recovery. Rehabilitation protocols should, therefore, emphasise post-operative strength training of the hip muscles. Additional research is needed to determine the consequences of reduced hip strength for the long-term outcome after arthroscopically treated FAI. Clinical relevance: The results of this study underline the importance of post-operative strength training prior to returning to sports in patients with femoroacetabular impingement surgery.

Level of evidenceIII.

I dag används styrketräning som ett komplement i prestationshöjande syfte i stort sett inom alla idrotter. Styrketräning spelar dessutom en stor roll inom idrotten när det gäller att förebygga och rehabilitera idrottsskador. Målsättningen med denna artikel är att ge exempel på hur styrketräning kan användas i förebyggande och rehabiliterande syfte, men även hur skador kan uppstå vid styrketräning.

Styrketräning kan utövas som en egen idrott i form av tyngdlyftning och styrkelyft. Styrketräning bedrivs också i prestationshöjande syfte som ett viktigt komplement till andra träningsformer eller idrotter. Många styrketränar för att orka mer och klara vardag och fritid bättre. Sist men inte minst spelar styrketräning en viktig roll i att förebygga och behandla skador och sjukdomar.

Styrketräning är inkluderande och kan utformas så att vem som helst, oberoende av ålder och fysisk status kan utföra den. Styrketräning är också skonsam och anpassningsbar och därför alltid ett alternativ när andra träningsformer blivit för krävande och inte längre fungerar att utföra. Styrketräning är dessutom en effektiv och utmanande träningsform, på kort tid kan man pressas till total utmattning.

Det är alltså inte så konstigt att styrketräning är en av de vanligaste träningsformerna och idag har mer än två miljoner utövare i Sverige. Och i takt med att intresset för styrketräning ökar, så bidrar forskningen till att kunskapen om kropp och muskler också ökar. Denna bok är den mest heltäckande och ambitiösa om styrketräning som skrivits i Sverige och ger såväl kunskap som vägledning kring hur styrketräning ska bedrivas för att ge optimal effekt utifrån träningens syfte. Boken är indelad i olika kapitel som behandlar många olika aspekter av styrketräning. För att öka förståelsen och för att göra läsningen så stimulerande som möjligt är boken rikt illustrerad och försedd med faktarutor och sammanfattningar.

Den nya upplagan av boken har både uppdaterats och utökats med nya forskningsrön, aktuella referenser och information i samtliga kapitel. Den tillämpade delen av boken har ytterligare fördjupats med nya bilder där de mest betydelsefulla styrketräningsövningarna demonstreras på ett unikt och pedagogiskt sätt för läsaren. Kapitlen Styrketräning för unga, gravida och äldre, Förebyggande och rehabiliterande styrketräning och Kostens betydelse vid styrketräning har alla nytt innehåll. Ett helt nytt kapitel, Träningsplanering och tester för styrketräning, har tillkommit.

Styrketräning – för idrott, motion och rehabilitering riktar sig bland annat till aktiva och ledare inom idrottsrörelsen, hälso-, friskvårds-, gym- och fitnessbranschens aktörer och till utbildningar av fysioterapeuter, idrottsvetare, hälsovetare, biomedicinare, idrottslärare med flera.