hamstring and quadriceps strength (ie, concentric and eccentric) and resistance to fatigue are important mechanisms for improving functional knee status in high level and recreational athletes. 3 Eccentric strength training has been demonstrated to be a substantial intervention for promoting neuromuscular
Eduardo Lusa Cadore, Miriam González-Izal, Rafael Grazioli, Igor Setuain, Ronei Silveira Pinto and Mikel Izquierdo
Daniel D. Cohen, Bingnan Zhao, Brian Okwera, Martyn J. Matthews and Anne Delextrat
To evaluate the effect of simulated soccer on the hamstrings eccentric torque-angle profile and angle of peak torque (APTeccH), and on the hamstrings:quadriceps torque ratio at specific joint angles (ASHecc:Qcon).
The authors assessed dominant-limb isokinetic concentric and eccentric knee flexion and concentric knee extension at 120°/s in 9 semiprofessional male soccer players immediately before and after they completed the Loughborough Intermittent Shuttle Test (LIST).
The LIST resulted in significant decreases in eccentric hamstrings torque at 60°, 50°, and 10° and a significant (21.8%) decrease in ASHecc:Qcon at 10° (P < .05). APTeccH increased from 7.1° ± 1.0° to 18.8° ± 4.2° (P < .05). Eccentric hamstrings peak torque significantly declined from 185.1 ± 70.4 N·m pre-LIST to 150.9 ± 58.5 N·m post-LIST (P = .002), but there were no significant changes in hamstrings or quadriceps concentric peak torque (P = .312, .169, respectively).
Simulated soccer results in a selective loss of eccentric hamstrings torque and hamstrings-to-quadriceps muscle balance at an extended joint position and a shift in the eccentric hamstrings APT to a shorter length, changes that could increase vulnerability to hamstrings injury. These findings suggest that injury-risk screening could be improved by evaluating the eccentric hamstrings torque-angle profile and hamstrings strength-endurance and that the development of hamstrings fatigue resistance and long-length eccentric strength may reduce injury incidence.
Helmi Chaabene, Yassine Negra, Jason Moran, Olaf Prieske, Senda Sammoud, Rodrigo Ramirez-Campillo and Urs Granacher
physical performance in team handball is of great importance. Resistance training is an effective way of increasing muscular strength in young females. 4 However, it has previously been shown that eccentric strength training is more effective than single-mode concentric or combined concentric
Mathieu Lacome, Simon Avrillon, Yannick Cholley, Ben M. Simpson, Gael Guilhem and Martin Buchheit
.80) 30/33/37 Unclear Knee-flexors eccentric strength, N 326.4 (48.1) 325.3 (26.2) 0.4 (10.2) 0.03 (0.76) 35/35/30 Unclear Expected knee-flexors strength, N 291.4 (20.5) 286.7 (23.0) −1.7 (6.3) −0.21 (0.80) 19/30/51 Unclear Δ Strength vs expected, % 11.7 (12.1) 14.1 (12.4) −1.4 (46.2) −0.03 (0.88) 33
Kris Beattie, Brian P. Carson, Mark Lyons and Ian C. Kenny
Maximum- and reactive-strength qualities both have important roles in athletic movements and sporting performance. Very little research has investigated the relationship between maximum strength and reactive strength. The aim of this study was to investigate the relationship between maximum-strength (isometric midthigh-pull peak force [IMTP PF]) and reactive-strength (drop-jump reactive-strength index [DJ-RSI]) variables at 0.3-m, 0.4-m, 0.5-m, and 0.6-m box heights. A secondary aim was to investigate the between- and within-group differences in reactive-strength characteristics between relatively stronger athletes (n = 11) and weaker athletes (n = 11). Forty-five college athletes across various sports were recruited to participate in the study (age, 23.7 ± 4.0 y; mass, 87.5 ± 16.1 kg; height, 1.80 ± 0.08 m). Pearson correlation results showed that there was a moderate association (r = .302–.431) between maximum-strength variables (absolute, relative, and allometric scaled PF) and RSI at 0.3, 0.4, 0.5 and 0.6 m (P ≤ .05). In addition, 2-tailed independent-samples t tests showed that the RSIs for relatively stronger athletes (49.59 ± 2.57 N/kg) were significantly larger than those of weaker athletes (33.06 ± 2.76 N/kg) at 0.4 m (Cohen d = 1.02), 0.5 m (d = 1.21), and 0.6 m (d = 1.39) (P ≤ .05). Weaker athletes also demonstrated significant decrements in RSI as eccentric stretch loads increased at 0.3-m through 0.6-m box heights, whereas stronger athletes were able to maintain their reactive-strength ability. This research highlights that in specific sporting scenarios, when there are high eccentric stretch loads and fast stretch-shortening-cycle demands, athletes’ reactive-strength ability may be dictated by their relative maximal strength, specifically eccentric strength.
Martin Buchheit, Yannick Cholley, Mark Nagel and Nicholas Poulos
To examine the effect of body mass (BM) on eccentric knee-flexor strength using the Nordbord and offer simple guidelines to control for the effect of BM on knee-flexor strength.
Data from 81 soccer players (U17, U19, U21, senior 4th French division, and professionals) and 41 Australian Football League (AFL) players were used for analysis. They all performed 1 set of 3 maximal repetitions of the bilateral Nordic hamstring exercise, with the greatest strength measure used for analysis. The main regression equation obtained from the overall sample was used to predict eccentric knee-flexor strength from a given BM (moderate TEE, 22%). Individual deviations from the BM-predicted score were used as a BM-free index of eccentric knee- flexor strength.
There was a large (r = .55, 90% confidence limits .42;.64) correlation between eccentric knee-flexor strength and BM. Heavier and older players (professionals, 4th French division, and AFL) outperformed their lighter and younger (U17–U21) counterparts, with the soccer professionals presenting the highest absolute strength. Professional soccer players were the only ones to show strength values likely slightly greater than those expected for their BM.
Eccentric knee-flexor strength, as assessed with the Nordbord, is largely BM-dependent. To control for this effect, practitioners may compare actual test performances with the expected strength for a given BM, using the following predictive equation: Eccentric strength (N) = 4 × BM (kg) + 26.1. Professional soccer players with specific knee-flexor-training history and enhanced neuromuscular performance may show higher than expected values.
Theofanis Tzatzakis, Konstantinos Papanikolaou, Dimitrios Draganidis, Panagiotis Tsimeas, Savvas Kritikos, Athanasios Poulios, Vasiliki C. Laschou, Chariklia K. Deli, Athanasios Chatzinikolaou, Alexios Batrakoulis, Georgios Basdekis, Magni Mohr, Peter Krustrup, Athanasios Z. Jamurtas and Ioannis G. Fatouros
eccentric strength of DL and NDL at 48 hours were lower than in C ( P < .05) (Table 6 ). In SEPT/1:8, KF eccentric strength of DL at 24 and 48 hours and KF eccentric strength of NDL were lower than in C ( P < .05). However, no differences were observed between the 2 SEPT trials. Table 6 Changes in
Athanasios Chatzinikolaou, Konstantinos Michaloglou, Alexandra Avloniti, Diamanda Leontsini, Chariklia K. Deli, Dimitris Vlachopoulos, Luis Gracia-Marco, Sotirios Arsenis, Ioannis Athanailidis, Dimitrios Draganidis, Athanasios Z. Jamurtas, Craig A. Williams and Ioannis G. Fatouros
pronounced in eccentric strength of KF and concentric strength of KE; (2) a 5-week periodized CT program not only attenuated the decline of strength/power performance observed during off-season detraining but also enhanced it; and (3) deterioration of endurance performance due to off-season detraining cannot
Justin W.Y. Lee, Ming-Jing Cai, Patrick S.H. Yung and Kai-Ming Chan
-third of all muscle injuries in elite soccer. 1 , 2 Previous studies suggested lower hamstring eccentric strength in the preseason increased the risk of future HSI. 3 – 6 Several large cohort studies revealed that modifying hamstring muscle strength through eccentric strength training exercises
Yassine Negra, Helmi Chaabene, Senda Sammoud, Olaf Prieske, Jason Moran, Rodrigo Ramirez-Campillo, Ali Nejmaoui and Urs Granacher
attributed the greater CoD improvements to the increased braking ability generated by the enhanced eccentric workload associated with loaded training. Sheppard and Young 27 suggest that PJT can improve eccentric strength of the thigh muscles, an important determinant of performance during the deceleration