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Performance of the Nordic hamstring exercise  

Performance of the Nordic hamstring exercise  

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Article
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Although changes in hamstring muscle morphology after anterior cruciate ligament reconstruction (ACLR) using a semitendinosus autograft hamstrings-gracilis (HG) of the ipsilateral limb are recognized, alterations in muscle activation patterns have not been extensively studied. The purpose of this controlled laboratory trial was therefore to monitor...

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... for the NH exercise, the lower extremities 178 are relatively free during the TRX performance. The NH 179 exercise was performed by each participant lowering their 180 trunk as slowly as possible, with arms at their side for as 181 long as possible (eccentric knee flexor activity from 95° 182 knee flexion while maintaining hips at close to 0°: Fig. ...

Citations

... Morbidity secondary to ACLR depends, in part, on the harvesting site, which also influences goals, milestones and progression of post-surgical rehabilitation. Functionally, harvesting from ST may result in persistent reduction of knee flexor muscle strength (Johnston, Feller, McClelland, and Webster, 2022) and altered muscle activation patterns (Arnason et al., 2014;Briem, Ragnarsdottir, Arnason, and Sveinsson, 2016). ...
Article
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Background Ultrasound (US) imaging is used by physical therapists for diagnosis and assessment of musculoskeletal injury and follow-up Purpose The aim was to identify long-term effects of graft harvesting on hamstrings muscle mass among athletes who had undergone anterior cruciate ligament reconstruction (ACLR). Methods Twenty-eight participants (ages 18–55) were recruited: 18 with history of ACLR using semitendinosus (ST) autograft and 10 healthy controls. Images of the cross-sectional area (CSA) of ST and biceps femoris (BF) were captured at 30% and 70% of the distance from the ischial tuberosity to the popliteal crease. A mixed model ANOVA was used to identify inter-limb differences in the CSA of ST and BF at each location, for each group Results Inter-limb differences were found for the CSA of ST but not BF across both locations for the ACLR group, not controls (p < .001). Within the ACLR group, ST atrophy of the injured limb was relatively greater at the distal vs. proximal location (p < .001). Conclusion US imaging identified selective atrophy of ST on the injured side with no compensatory hypertrophy of BF. Specific rehabilitation may influence muscle mass of medial vs. lateral hamstrings muscle groups after ACLR using a ST graft, and monitored with US imaging.
... 2 3 The semitendinosus and/or gracilis tendons do not regenerate in ~30% of ACLR patients. 4 Moreover, ACLR patients often have long-term deficits in knee flexor and internal rotator strength, [5][6][7] as well as altered knee biomechanics, [8][9][10] muscle activation patterns [11][12][13] and knee function (patient-reported outcomes measure, PROM). 14 15 These chronic deficits in knee function are thought due, in part, to ...
Article
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Introduction Anterior cruciate ligament (ACL) rupture is debilitating, often requiring surgical reconstruction. An ACL reconstruction (ACLR) using a tendon autograft harvested from the semitendinosus results in substantial injury to the donor muscle. Following ACLR, patients rarely return to their preinjury level of physical activity, are at elevated risk of secondary lower limb injuries and early onset knee osteoarthritis. To date, no randomised controlled trial has evaluated the efficacy of platelet-rich plasma (PRP) in aiding knee function and semitendinosus morphology of following ALCR. Methods and analysis This is a multicentre double-blind randomised placebo-controlled trial. Fifty-four ACLR patients aged 18–50 years will be randomised to receive either a single application of PRP (ACLR+) or placebo saline (ACLR) into the semitendinosus harvest zone at the time of surgery. All patients will undergo normal postoperative rehabilitation recommended by the attending orthopaedic surgeon or physiotherapist. The primary outcome measure is between-limb difference (ACLR compared with intact contralateral) in isometric knee flexor strength at 60 o knee flexion, collected 10–12 months postsurgery. This primary outcome measure will be statistically compared between groups (ACLR+ and standard ACLR). Secondary outcome measures include bilateral assessments of hamstring muscle morphology via MRI, biomechanical and electromyographic parameters during an anticipated 45° running side-step cut and multidirectional hopping task and patient-reported outcomes questionaries. Additionally, patient-reported outcomes questionaries will be collected before (baseline) as well as immediately after surgery, and at 2–6 weeks, 3–4 months, 10–12 months and 22–24 months postsurgery 10–12 months following surgery. Ethics and dissemination Ethics approval has been granted by Griffith University Human Research Ethics Committee, Greenslopes Research and Ethics Committee, and Royal Brisbane & Women’s Hospital Human Research Ethics Committee. Results will be submitted for publication in a peer-reviewed medical journal. Trial registration number ACTRN12618000762257p.
... Although this procedure is admittedly hard to realize in the field, individual thresholds to terminate an exercise set (e.g., ROM to downward acceleration <30 • ) should be implemented rather than predefining a fixed exercise volume. To improve the acute or chronic performance and quality of NHE execution by elevated motivation and effort [39,117], the use of visual and verbal feedback is recommended [6,42,106,117]. In cases where the optimal 1:1 coach-to-athlete ratio is not feasible (e.g., in larger samples), the athletes might give feedback to their training partner. ...
... Although this procedure is admittedly hard to realize in the field, individual thresholds to terminate an exercise set (e.g., ROM to downward acceleration <30 • ) should be implemented rather than predefining a fixed exercise volume. To improve the acute or chronic performance and quality of NHE execution by elevated motivation and effort [39,117], the use of visual and verbal feedback is recommended [6,42,106,117]. In cases where the optimal 1:1 coach-to-athlete ratio is not feasible (e.g., in larger samples), the athletes might give feedback to their training partner. ...
Article
Full-text available
ABSTRACT: The objective of this scoping review is to assess Nordic Hamstring Exercise quality (ANHEQ) of assessments and interventions according to the ANHEQ rating scales and to present practical recommendations for the expedient design and reporting of future studies. A total of 71 Nordic Hamstring Exercise (NHE) assessments and 83 NHE interventions were selected from the data sources PubMed, Scopus, and SPORTDiscus. Research studies which were presented in peer-reviewed academic journals and implemented the NHE during laboratory-based assessments or multi-week interventions met the eligibility criteria. NHE assessments analyzed force (51%), muscle activation (41%), knee angle kinematics (38%), and bilateral symmetry (37%). NHE interventions lasted 4–8 weeks (56%) and implied an exercise volume of two sessions per week (66%) with two sets per session (41%) and ≥8 repetitions per set (39%). The total ANHEQ scores of the included NHE assessments and interventions were 5.0 ± 2.0 and 2.0 ± 2.0 (median ± interquartile range), respectively. The largest deficits became apparent for consequences of impaired technique (87% 0-point-scores for assessments) and kneeling height (94% 0-point-scores for interventions). The 0-point-scores were generally higher for interventions compared to assessments for rigid fixation (87% vs. 34%), knee position (83% vs. 48%), kneeling height (94% vs. 63%), and separate familiarization (75% vs. 61%). The single ANHEQ criteria, which received the highest score most frequently, were rigid fixation (66% of assessments) and compliance (33% of interventions). The quality of NHE assessments and interventions was generally ‘below average’ or rather ‘poor’. Both NHE assessments and interventions suffered from imprecise reporting or lacking information regarding NHE execution modalities and subsequent analyses. Based on the findings, this scoping review aggregates practical guidelines how to improve the design and reporting of future NHE-related research.
... Although this procedure is admittedly hard to realize in the field, individual thresholds to terminate an exercise set (e.g., ROM to downward acceleration <30 • ) should be implemented rather than predefining a fixed exercise volume. To improve the acute or chronic performance and quality of NHE execution by elevated motivation and effort [39,117], the use of visual and verbal feedback is recommended [6,42,106,117]. In cases where the optimal 1:1 coach-to-athlete ratio is not feasible (e.g., in larger samples), the athletes might give feedback to their training partner. ...
... Although this procedure is admittedly hard to realize in the field, individual thresholds to terminate an exercise set (e.g., ROM to downward acceleration <30 • ) should be implemented rather than predefining a fixed exercise volume. To improve the acute or chronic performance and quality of NHE execution by elevated motivation and effort [39,117], the use of visual and verbal feedback is recommended [6,42,106,117]. In cases where the optimal 1:1 coach-to-athlete ratio is not feasible (e.g., in larger samples), the athletes might give feedback to their training partner. ...
Preprint
OBJECTIVE: Assessing Nordic Hamstring Exercise quality (ANHEQ) of assessments and interventions according to the ANHEQ rating scales and to present practical recommendations for the expedient design and reporting of future studies. DESIGN: Scoping review of 71 NHE assessments and 83 NHE interventions (12 of 131 full-text articles were applicable to both categories). DATA SOURCES: PubMed, MEDLINE and SPORTDiscus. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Research studies which were presented in peer-reviewed academic journals and implemented the NHE during laboratory-based assessments or multi-week interventions. RESULTS: The total ANHEQ scores of the analysed NHE assessments and interventions were 5.0±2.0 and 2.0±2.0 (median±IQR), respectively. Largest deficits became apparent for consequences of impaired technique (87% 0-point-scores for assessments) and kneeling height (94% 0-point-scores for interventions). The single ANHEQ criteria which received the highest score most frequently were rigid fixation (66% of assessments) and compliance (33% of interventions). CONCLUSIONS: The quality of NHE assessments and interventions was generally ‘below average’ or rather ‘poor’. Practitioners and scientists are encouraged to provide detailed information about their NHE modalities and about how their participants performed the exercise. The appropriate setup is suggested to be essential for best possible NHE performance and neuromuscular adaptations. NHE assessments should present comprehensive kinematic and kinetic data of supramaximal NHE performance, whereas NHE interventions should focus on exercise intensity and the implementation of facilitations. This scoping review aggregates practical guidelines how to improve the design and reporting of future NHE assessments and interventions to overcome the revealed limitations of current NHE-related evidences.
... Therefore, it can be concluded that the removal of the graft from the semi-tendinous cannot be assimilated to an HSI. These are the same data found in a 2019 study [13], which concluded that the MEA of the knee flexors after ACLR with hamstring graft to evolve towards extension. In addition, this study compared the evolution of MEA as a function of patient rehabilitation time (supervised rehabilitation of more than 6 months or less than 6 months). ...
... We also find data similar to those of the 2018 study [12] with concordant MEA differences: -10.10 ° difference between the 3-month assessment and the control group -8.5 ° difference between the assessment at 6 months and the control group No precise explanation has been provided to date as to the reasons for this change in the MEA's position after an ACLR. Despite this, the most discussed and explored theory [13] brings into play the decrease in the activity of the semitendinous (ST) in favor of an increase in the activity of the Biceps Femoris (BF) especially during activities requiring intense efforts. Hamstring morphology, strength [15], and neuromuscular activity [13] are altered after ACLR and may remain altered for up to 6 years after surgery. ...
... Despite this, the most discussed and explored theory [13] brings into play the decrease in the activity of the semitendinous (ST) in favor of an increase in the activity of the Biceps Femoris (BF) especially during activities requiring intense efforts. Hamstring morphology, strength [15], and neuromuscular activity [13] are altered after ACLR and may remain altered for up to 6 years after surgery. More particularly, BF and ST are the primary muscles affected by the operation [13]. ...
Article
Background: During the anterior cruciate ligament reconstruction, the graft is taken from the distal hamstring tendon, which causes morphological and neurological changes in these muscles, particularly on the maximum effective angle of the knee flexors. The present study investigates changes in knee flexor following anterior cruciate ligament reconstruction with a hamstring graft. Methods: Two populations participated in this study, a healthy group and a group that underwent anterior cruciate ligament reconstruction with a hamstring graft. First, the test group underwent two postoperative assessments on an isokinetic device at 3 and 6 months. Next, we compared the test group at 3 and 6 months with the control group to highlight the differences between the knee flexors maximum effective angle. And finally, we have compared the knee flexors maximum effective angle with the moment of maximum force to determine whether these two values are related. Results: The maximum effective angle is decreased regardless of the duration of rehabilitation (ρ= 0.0019, ρ = 0.037). It does not change significantly during rehabilitation (ρ = 0.29). It does not depend on the strength gained during rehabilitation but on a neuromotor change due to the morphological changes caused by surgery. Conclusion: The study results show that anterior cruciate ligament reconstruction with hamstring graft causes a decrease in knee flexor maximum effective angle.
... During functional performance, the hamstring is a key muscle in the stabilization of the knee, most notably, anterior translation and rotation. 19,20 Consequently, these 2 movement patterns, through differing planes, are largely associated with anterior cruciate ligament (ACL) injury. 6,21,22 Consequently, implications may also be observed inferiorly to the knee, potentially affecting the ankle joint control mechanisms. ...
... Anterior cruciate ligament injuries sustained in footballers are commonly associated with an increased anterior shearing force, resulting in excessive load being exerted through the ACL. 19,20 It is suggested that decreased functional strength of the hamstrings may have an impact on DDS performance, 9 and, with the addition of acute fatigue exposure or insufficient recovery, this risk could be heightened. Combined with the additional rotational load, potentially creating further damage to major joint structures, these injuries can result in significant time loss for the athlete. ...
... 19,22,23 The hamstrings are a key muscle group, providing support to the knee joint through these movement patterns, best explained by understanding its functional anatomical role in performance. 20 Future work should consider quantifying muscle activity in relation to dynamic stability output with the use of electromyography. The present study identifies significantly elevated A-P stability scores throughout all time points compared with M-L (14%-25%), which potentially indicates the vulnerability of the ACL to increased anterior load exposure during performance. ...
Article
Background: Rising injury rates within football require further understanding of the etiological risk factors associated with lower-limb injury. Aim: To examine the temporal pattern of recovery of directional dynamic stability measures post football-specific fatigue. Methods: Eighteen male elite footballers completed baseline assessments of directional dynamic stability measures (Overall Stability Index, anterior-posterior stability [A-P], medial-lateral stability [M-L] on level 1 of the Biodex Stability System). Post Soccer-Specific Aerobic Field Test90 measures were repeated immediately, +24 hours, +48 hours, and +72 hours. The main effects for the recovery time and direction of stability were supplemented by regression modeling to describe the temporal pattern of recovery. Results: Significant main effects for time were identified for all directions of stability (Overall Stability Index, A-P, and M-L) up to +48 hours postexercise (P ≤ .05). The quadratic pattern of temporal recovery highlights a minimum of 37.55 to 38.67 hours and maximum of 75.09 to 77.33 hours. Additionally, a main effect for direction of stability was observed, with significant differences identified between A-P and M-L stability at all time points (P ≤ .001). Conclusions: Reductions in directional dynamic stability +48 hours postfatigue highlight implications for training design, recovery strategies, and injury management for performance practitioners. Interestingly, A-P stability has been highlighted as being significantly reduced compared with M-L stability at all time points, regardless of the fatigue exposure. Practitioners should consider the reduction of stability in this plane in relation to common mechanisms of injury in the knee to inform injury-risk-reduction strategies.
... Although the consensus across literature appears clear for the hamstring, the effect of increased functional hamstring strength on the stability of the knee is limited. Research highlights that players who sustain an ACL rupture display significant reductions in hamstring function, post-injury or surgical intervention (Arnason et al. 2014;Kim et al. 2016), increasing the risk of re-rupture. Previous injury is highlighted as a key aetiological factor in the recurrence of ACL ruptures (Alentorn-Geli et al. 2009;Harput et al. 2015). ...
Article
Objectives Previous research describes dynamic stability and functional strength as key aetiological risk factors associated with lower limb non-contact musculoskeletal injury. Due to the multi factorial nature of injury risk, relationships between the two factors will inform injury management and training design. Methods Fifty-nine elite academy footballers from two English premier league category 1-status academies completed the study. All players completed measures of eccentric hamstring strength and dynamic stability. Relationships between directional stability (Anteroposterior (Ant), Posteromedial (PM) and Posterolateral (PL)) and eccentric strength metrics (PkT, AvT, PkF, AvF and Ɵ) bilaterally were identified for analysis. Results Significant correlations were identified bilaterally for functional hamstring strength metrics and PM and PL stability (P ≤. 0.05). No significant relationships were identified between anterior stability and eccentric hamstring strength parameters (P > 0.05). Conclusions Eccentric hamstring strength has a positive influence on directional stability through two planes, PM and PL. The lack of influence of eccentric hamstring strength on Ant directional stability could be attributed to increased ACL risk. Careful consideration of the significance of the relationships between eccentric hamstring strength and directional stability must be given when quantifying injury risk in elite academy footballers.
... Twenty men and 20 women meeting inclusion criteria were recruited from the university community for this cross-sectional laboratory study and participated in a single measurement session. Sample size was determined based on the laboratory's previous research using electromyographic (EMG) measures 4,6 where observed power of 2 groups with 20 subjects each ranged from 0.7 to over 0.9 for 2-and 3-way interactions with alpha set at 0.05, also providing adequate power for analysis of strength data. Exclusion criteria consisted of history of knee surgery or any serious neuromusculoskeletal injury of the lower limbs; lesser injury (not leading to modification of activities) of the hamstring, gluteal, or back muscles in the 3 months prior to data collection; knee pain during the 3 previous months; and a body mass index (BMI) of greater than 35 kg/m 2 . ...
... The raw EMG data were high-pass filtered at 25 Hz, full wave rectified, and the root mean square of the signal was derived using a moving window of 250 ms according to the laboratory's protocol. 4,6 Maximum values of the smoothened data were then identified within each 5-second measurement and normalized to the maximum signal obtained after warm-up during a standard maximal voluntary isometric contraction obtained in a prone position at 25° of knee flexion with a neutral tibial position. ...
Article
Full-text available
Background: Selective atrophy of hamstring components may result from muscle strain or graft harvesting for anterior cruciate ligament reconstruction. Assessment and rehabilitation that specifically targets medial (MH) or lateral (LH) hamstring components may improve patient outcomes. The purpose of this study was to evaluate effects of volitional tibial rotation medially (MR) versus laterally (LR) on activation levels of MH versus LH and strength measures during isometric testing of knee flexors. Hypothesis: Muscle activation of MH and LH during knee flexor strength testing will be augmented when coupled with MR and LR of the tibia, respectively, without affecting knee flexor strength measures. Study design: Cross-sectional laboratory study. Level of evidence: Level 3. Methods: Surface electrodes were used to record neuromuscular activity from MH and LH of the right lower limb in 40 healthy young men and women during isometric knee flexor strength testing at 40° of knee flexion, where participants maintained concurrent volitional MR or LR of the tibia. Statistical analyses of variance included general linear models for repeated measures. Results: A significant interaction was found for tibial rotation and hamstring component variables (P < 0.01). When isometric knee flexion was coupled with LR, normalized activation levels were similar for MH and LH. When performed with MR, a significant drop in LH activation led to dissimilar activation levels of the 2 components. Significantly greater strength measures were found when isometric knee flexion was performed with concurrent LR of the tibia (P < 0.01). Both sexes demonstrated the same rotation-dependent differences. Conclusion: Coupling tibial rotation with knee flexor activities primarily affects the LH component. Clinical relevance: Strategies involving volitional tibial rotation may be considered for specific assessment/rehabilitation of the MH or LH component.
... 9 On the other hand, a recent study that investigated medial hamstring myoelectric activation patterns found that at 6 years after ACLR they are still abnormal. 17 Longitudinal studies with longer follow-up are needed to determine the recovery of knee flexion strength in the longer term. ...
Article
Hamstrings grafts are commonly used in ACL reconstruction, however, the effect of graft harvesting on knee flexion strength has not been longitudinally evaluated in functional positions. We hypothesized that greater deficits in knee flexion strength exist in the prone compared to the seated position and these deficits remain as rehabilitation progresses. Case series. Forty-two consecutive patients who underwent ACL reconstruction with a hamstrings graft were followed prospectively for 9 months. Isokinetic knee flexion strength at a slow and a fast speed were collected at 3, 4, 6, and 9 months in two different positions: conventional (seated) and functional (0° of hip flexion). Peak torque knee flexion deficits were higher in the prone position compared to the seated position by an average of 6.5% at 60°/s and 9.1% at 180°/s (p<0.001). Measuring knee flexion strength in prone demonstrates higher deficits than in the conventional seated position. Most athletes would not be cleared to return to sports even at 9 months after surgery with this method. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Article
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The semitendinosus tendon is commonly harvested as graft tissue for anterior cruciate ligament reconstruction (ACLR). Although the semitendinosus tendon can regenerate following harvesting, ACLR results in substantial reductions in semitendinosus muscle size and length, potentially complicating electrode placement for electromyography. The purpose of this study was to assess whether the most commonly used electrode placement [recommended by the “Surface Electromyography for Non-Invasive Assessment of Muscles” (SENIAM) project] is appropriate for measuring semitendinosus electromyograms after ACLR. In nine participants (unilateral ACLR with a semitendinosus graft), B-mode ultrasonography was used to bilaterally determine (i) the semitendinosus muscle-tendon junction position and the state of tendon regeneration (latter for the ACLR leg only) and (ii) the anatomical cross-sectional area (ACSA) of the semitendinosus muscle at the SENIAM-recommended electrode placement site at rest and during isometric maximal voluntary contraction (MVC) at two knee joint angles. Depending on the contraction state and joint angle, the semitendinosus muscle had retracted past the recommended placement site in 33–78% of ACLR legs, but not in any contralateral legs. The ACSA of semitendinosus was smaller both at rest and MVC in the ACLR compared to contralateral leg. The ACSA for both legs decreased at MVC compared to rest and at deep compared to shallow knee flexion angles, likely due to sliding of the muscle under the skin. These results suggest SENIAM guidelines are likely unsuitable for recording surface electromyograms from the semitendinosus muscle after tendon harvesting for ACLR as the muscle of interest may not be within the electrode detection volume.