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Early versus Delayed Rehabilitation after Acute Muscle Injury


Abstract and Figures

In this randomized study involving 50 amateur athletes with severe injury to thigh or calf muscles, a return to full activity was more rapid when the rehabilitation program was started 2 days rather than 9 days after injury.
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Cor responde nce
The new england journal of medicine
n engl j med 377;13 September 28, 2017
Cor responde nce
Early versus Delayed Rehabilitation after Acute Muscle Injury
To the Editor: Acute traumatic muscle-strain
injuries are common and result in a substantial
loss of time and risk of recurrence. Treatment op-
tions such as platelet-rich plasma are ineffective.
The extent to which the timing of rehabilitation
inf luences clinical recovery of strain injuries re-
mains unknown. We investigated whether early
or delayed use of injured musculotendinous tissue
affected recovery after acute muscle-strain injuries.
We conducted a randomized, controlled trial
involving 50 amateur athletes with acute injury
of the thigh muscle (in approximately 60% of
the patients) or calf muscle (in approximately
40%), as confirmed on ultrasonography and mag-
netic resonance imaging. Patients (mean age, 34
years) were recruited less than 48 hours after
injury and underwent randomization to receive
early therapy (2 days after injury) or delayed
therapy (9 days after injury) and were followed
for 12 months. The injuries were most com-
monly associated with playing soccer or partici-
pating in track-and-field events. (Details regard-
ing the types of injuries are provided in the
Supplementary Appendix, available with the full
text of this letter at
All the patients completed a standardized
four-stage therapy regimen: daily repeated static
stretching (week 1), daily isometric loading with
increasing load (weeks 2 to 4), dynamic loading
with increasing resistance three times per week
(weeks 5 to 8), and functional exercises combined
with heavy strength training three times per week
(weeks 9 to 12). Five patients in the early-therapy
group and three in the delayed-therapy group
discontinued treatment. The primary outcome
was a return to sports, which was def ined as the
first time point of full participation in sports
after being asymptomatic and successful com-
pletion of a functional test (a score of ≤1 on the
Numeric Pain Rating Scale, which ranges from
0 to 10 with higher scores indicating a greater
level of pa in).
The interval between severe muscle injury and
a return to sports was shorter in the early-therapy
group than in the delayed-therapy group, with a
median interval of 62.5 days (interquartile range,
48.8 to 77.8) and 83.0 days (interquartile range,
64.5 to 97.3), respectively (P = 0.01) (Fig. 1). Re-
injury during the follow-up period occurred in
one patient in the early-therapy group and in no
patients in the delayed-therapy group.
This study shows the clinical consequences of
protracted immobilization after a recreational
sports injury. Starting rehabilitation 2 days after
injury rather than waiting for 9 days shortened
the interval from injury to pain-free recovery and
return to sports by 3 weeks without any signif i-
cant increase in the risk of reinjury. The observed
difference supports the importance of early load-
ing of injured musculotendinous tissue. Immo-
bilization can swiftly and adversely affect muscle
and tendon structure and function and has detri-
mental effects on connective-tissue cells.
this week’s letters
1300 Early versus Delayed Rehabilitation after Acute
Muscle Injury
1301 Prostatectomy versus Observation for Early
Prostate Cancer
1303 Changes in Diet Quality and Total
and Cause-Specif ic Mortality
1305 Beating, Fast and Slow
The New England Journal of Medicine
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Copyright © 2017 Massachusetts Medical Society. All rights reserved.
Cor re spondence
n engl j med 377;13 September 28, 2017
matrix component of muscle–tendon regeneration
is substantial and prolonged,
which may con-
tribute to the difference in recovery time in our
study. Delay in rehabilitation can result in pro-
longed pain and a delayed return to sports, a
finding that emphasizes the importance of regu-
lar and controlled mechanical loading early after
trauma to large muscles.
Monika L. Bayer, Ph.D.
S. Peter Magnusson, P.T., D.M.Sc.
Michael Kjaer, M.D., D.M.Sc.
Bispebjerg Hospital
Copenhagen, Denmark
monika . lucia . bayer@ regionh . dk
for the Tendon Research Group Bispebjerg
A complete list of members of the Tendon Research Group
Bispebjerg is provided in the Supplementa ry Appendix, avai lable
Supported by Bispebjerg Hospita l, Great er Region of Copen-
hagen Research Foundat ion, Dan ish Rheu matism Association,
Lundbeck Foundat ion, Danish Council for Independent Research,
Novo Nordisk Foundation, and Anti Doping Denma rk.
Disclosure forms provided by the aut hors are available wit h
the fu ll text of th is letter at
1. Reu rink G, Goudswaard GJ, Moen MH, et al. Platelet-rich
plasma inject ions in acute muscle i njur y. N Engl J Med 2014; 370:
2 54 6 - 7.
2. de Boer MD, Maganar is CN, Seynnes OR, Rennie MJ, Narici
MV. Time course of muscula r, neura l and tendinous adaptations
to 23 day unilatera l lower-limb suspension in young men. J Physiol
2007; 583: 1079-91.
3. Bayer ML, Schjerling P, Herchenhan A, et al. Release of ten-
sile str ain on engineered huma n tendon t issue disturbs cell ad-
hesions, changes matri x architect ure, and induces an inf l am-
matory phenotype. PLoS One 2014; 9(1): e86078.
4. Mackey AL, Brandstet ter S, Schjerling P, et al. Sequenced
response of extracellu lar matri x deadhesion and f ibrotic regu la-
tors af ter muscle damage is involved in protection against fut ure
injur y in human skeletal muscle. FASEB J 2011; 25: 1943-59.
DOI: 10.1056/NEJMc1708134
Prostatectomy versus Observation for Early Prostate Cancer
To the Editor: In reporting the results of the
Prostate Cancer Intervention versus Observation
Trial (PIVOT), Wilt et al. (July 13 issue)
no significant decrease in all-cause or prostate-
cancer mortality among men assigned to sur-
gery, as compared with those assigned to ob-
servation (hazard ratio, 0.84; 95% confidence
interval, 0.70 to 1.01; P = 0.06). These results al-
most certainly reflect a type II error from a lack
of power. The authors enrolled 731 men from a
targeted accrual of 2000 men. Doubling the trial
cohort to 1462 patients (still well short of the
targeted accrual) would have resulted in a 76%
probability of a signif icant effect.
Furthermore, 74% of the cohort had low-grade
cancer. These men probably would not have died
from prostate cancer. Meaningful differences in
survival among men with prostate cancer were
likely to be seen only in the 26% of patients with
a score of 7 or higher on the Gleason scale (a
scale of 2 to 10, with higher scores indicating
a high-grade histologic subtype of prostate tu-
Figure 1. Interval from Muscle-Strain Injury to Pain-free
Full Recovery, According to the Timing of Initiation of
Rehabilitation Therapy.
Panel A shows the number of days from injury to recovery
among the 50 patients who received early rehabilitation
(starting 2 days after injur y) or delayed rehabilitation
(starting 9 days after injur y). Panel B shows the median
number of days from injury to recovery; the I bars indicate
the interquartile range.
Patient Recovery (%)
0 30 6050 90 120 150 233
Days since Injury
BMedian No. of Days until Recovery
AInterval between Injury and Recovery
Early-therapy group
No. of Days until Recovery
0Early-Therapy Group Delayed-Therapy Group
The New England Journal of Medicine
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Copyright © 2017 Massachusetts Medical Society. All rights reserved.
... This is a topic of clinical interest because BFlh is very susceptible to muscle injury and this condition may be exacerbated by disuse exposure, potentially also in the not-injured limb. The most recent recommendations for the lower limb musculoskeletal injuries treatment generally suggest that early rehabilitation interventions after the acute phase postinjury or after surgery are more successful for the return to play or to habitual daily motor tasks (32). We investigated the time course of HS structural and contractile properties changes during 10 d of BR. ...
... These findings could be useful from a clinical perspective, as such short periods of unloading can be experienced after musculoskeletal injuries and/or orthopedic surgeries, although we acknowledge that BR and postinjury/surgery conditions represents two distinct scenarios (5). Our results also support the view that early rehabilitation interventions are needed after the acute phase postinjury and surgery for a more successful return to play or to habitual daily motor tasks (32). Moreover, in such scenarios, the inflammatory response induced by the injury can exacerbate muscle loss through the activation of specific molecular pathways (56): for instance, recreational football players with HS strain injuries experienced a more marked HS volume loss in the injured versus healthy limb (6.7% vs 2.2%) at 3 wk after the injury event (57). ...
Purpose: The hamstrings (HS) muscle group plays a fundamental role in maintaining knee stability, thus contributing to the prevention and rehabilitation of lower limb musculoskeletal injuries. However, little is known about HS structural and functional adaptations after periods of prolonged inactivity. Our purpose was to investigate the HS morphological and contractile properties changes during 10 days of bed rest (BR). Methods: Ten young healthy males underwent a 10-day BR. HS cross-sectional area (CSA) (at 30%, 50%, and 70% of femur length), biceps femoris long head (BFlh) architecture were assessed by ultrasound imaging after 0 (BR0), 2 (BR2), 4 (BR4), 6 (BR6) and 10 (BR10) days of BR, while BFlh contractile properties (radial twitch displacement (Dm); contraction time (Tc)) were evaluated at the same time points by tensiomyography. HS muscle volume was assessed by magnetic resonance imaging at BR0 and BR10. Results: A reduction in muscle volume was observed in BFlh (p = 0.002; Δ = -3.53%), biceps femoris short head (p = 0.002; Δ = -3.54%), semitendinosus (p = 0.002; Δ = -2.63%), semimembranosus (p = 0.002; Δ = -2.01%) and HS pooled together (p < 0.001; Δ = -2.78%). Early changes in CSA were detected at 30% femur length already at BR6 for BFlh (p = 0.009; Δ = -2.66%) and BFsh (p = 0.049; Δ = -1.96%). We also found a reduction in fascicle length (Lf) at BR6 (p = 0.035; Δ = -2.44%) and BR10 (p < 0.001; Δ = -2.84%). Dm and Tc increased at BR2 (p = 0.010; Δ = 30.0%) and B10 (p = 0.019; Δ = 19.7%), respectively. Conclusions: Despite being a non-postural muscle group, HS exhibited a moderate reduction in muscle dimensions in response to a short unloading period. Small changes in BFlh Lf were also observed, accompanied by alterations in BFLh contractile properties. These HS modifications should not be ignored from a clinical perspective.
... However, such an ap-proach was often extended by clinicians for more than just the recommended first days, and athletes were asked to limit mobilisation of their injured muscle for 1, 2, or 3 weeks. There is now evidence, in animals [11] and humans [12], that rest is not the best approach to promote muscle healing and a return to sports. Starting rehabilitation (strengthening and stretching) earlier allows for an earlier return to sport [12]. ...
... There is now evidence, in animals [11] and humans [12], that rest is not the best approach to promote muscle healing and a return to sports. Starting rehabilitation (strengthening and stretching) earlier allows for an earlier return to sport [12]. Thus, Dubois and Esculier [13] suggested a recent approach for softtissue injuries, including muscle injuries, called PEACE & LOVE, emphasizing "Load", as an active approach with movement and exercise, by adding controlled mechanical stress early and promoting resumption of normal activities as soon as symptoms allow [13]. ...
... In contrast, microwave heating has been applied with relative success [33]. Platelet-rich plasma injections have also been tested but showed no effect compared to the control [34,35]. Extracorporeal shock wave therapy can accelerate regeneration after acute skeletal muscle injury [36], but it requires many applications over several weeks. ...
Full-text available
Muscle regeneration after a traumatic injury can take an excessively long period of time. The purpose of this study is to assess whether the action of percutaneous needle electrolysis (PNE) accelerates muscle regeneration in cases of partial muscle injuries. The gastrocnemius muscle from adult Swiss male mice was inoculated with bupivacaine. The PNE protocol was applied 48 h after treatment with bupivacaine. Immunofluorescence techniques were performed 72 h after treatment with bupivacaine to evaluate the synaptic contacts. The end plate noise was recorded by electromyography after treatment with bupivacaine. Bupivacaine induced a local injury in muscles, axons were retracted, and the endplate noise decreased at 72 h, while the endplate noise increased in the injured limb where PNE had been applied. Seven days later, the functional values were the same as the controls and they were maintained for 10 days. The endplate noise was significantly greater on the limb treated with the electric current when compared to the limb receiving only bupivacaine, indicating that the use of galvanic current facilitated muscle regeneration at least from a functional point of view. The application of PNE during muscle regeneration in an animal model reduces the recovery time of the damaged muscle tissue.
... Interestingly, several weeks of exposure to heavy load concentric exercise have been shown to shorten biceps femoris fascicles [4]. Typically heavy eccentric exercise has not been programmed during competition phases or during acute stages of rehabilitation [5][6][7], with previous expert recommendation specifically against this in early rehabilitation [8]. Recently, rehabilitation practices have shifted toward the earlier introduction of eccentric (lengthening) type exercises [9][10][11]. ...
Full-text available
Objectives. Document changes in fascicle length during rehabilitation from hamstring injury of the injured and uninjured legs and secondarily to describe any association between these changes and reinjury rate. Design. Multicentre case series. Methods. Fifty-two prospectively included hamstring injured athletes had their biceps femoris long head fascicle lengths measured at the start and end of rehabilitation using two-dimensional ultrasound. Absolute and relative changes in fascicle length were compared for each leg using linear mixed models. Participants were followed for six months after being cleared to return to sport for any reinjury. Fascicle lengths and rehabilitation duration were compared for those who reinjured and those who did not. Results. Injured leg fascicle length was shorter at the start of rehabilitation (9.1 cm compared to 9.8 cm, p<0.01 ) but underwent greater absolute and relative lengthening during rehabilitation to 11.1 cm (18% increase) compared to 10.2 cm (8% increase, p<0.01 ) for the uninjured leg. There were no significant differences in any fascicle length parameter for the 5 participants who reinjured in the 6 months following their return to sport compared to those that did not reinjure. Conclusions. While both injured and uninjured legs displayed increases in fascicle length during rehabilitation, the larger fascicle length increases in the injured leg suggest that either a different training stimulus was applied during rehabilitation to each leg or there was a different response to training and/or recovery from injury in the injured leg. Reinjury risk appears to be independent of fascicle length changes in this cohort, but the small number of reinjuries makes any conclusions speculative.
... The Bayer trial used a time-based protocol and they did not start with dynamic eccentric exercises before week five. 36 In the Hickey trial, they compared similar eccentric exercises (that were initiated early in both groups), but with different pain threshold. In our study, both protocols were performed within pain free limit. ...
Full-text available
Background To evaluate the efficacy of early versus delayed introduction of lengthening (ie, eccentric strengthening) exercises in addition to an established rehabilitation programme on return to sport duration for acute hamstring injuries in a randomised controlled superiority trial. Methods 90 male participants (age: 18–36 years, median 26 years) with an MRI-confirmed acute hamstring injury were randomised into an early lengthening (at day 1 of rehabilitation) group or a delayed lengthening (after being able to run at 70% of maximal speed) group. Both groups received an established rehabilitation programme. The primary outcome was time to return to sport (ie, time from injury to full unrestricted training and/or match play). The secondary outcome was reinjury rate within 12 months after return to sport. Other outcomes at return to sport included the Askling H-test, hamstring strength, clinical examination and readiness questions. Results The return to sport in the early lengthening group was 23 (IQR 16–35) days and 33 (IQR 23–40) days in the delayed lengthening group. For return to sport (in days), the adjusted HR for the early lengthening group compared with the delayed lengthening group was 0.95 (95% CI 0.56 to 1.60, p=0.84). There was no significant difference between groups for reinjury rates within 2 months (OR=0.94, 95% CI 0.18 to 5.0, p=0.94), from 2 to 6 months (OR=2.00, 95% CI 0.17 to 23.3, p=0.58), and 6 to 12 months (OR=0.57, 95% CI 0.05 to 6.6, p=0.66). Conclusion Accelerating the introduction of lengthening exercises in the rehabilitation of hamstring injury in male athletes did not improve the time to return to sport nor the risk of reinjury.
... CMSI calf muscle strain injuries, MTPJ metatarsophalangeal joint had the opportunity to commence loading. Data from recent studies support this concept-early loading of CMSI results in faster recovery [41] and may improve pain and confidence [42], irrespective of injury characteristics such as the muscle involved, anatomical location of injury, and tissue type injured. Despite the recent shift away from managing muscle strains according to the estimated time taken for the underlying pathology to resolve, as recommended by Hickey et al. for hamstring strain injuries [43], experts did highlight situations where pathology was believed to be an important consideration for selecting exercises and planning functional progression. ...
Full-text available
Background Despite calf muscle strain injuries (CMSI) being problematic in many sports, there is a dearth of research to guide clinicians dealing with these injuries. The aim of this study was to evaluate the current practices and perspectives of a select group of international experts regarding the assessment, management and prevention of CMSI using in-depth semi-structured interviews. Results Twenty expert clinicians working in elite sport and/or clinician-researchers specialising in the field completed interviews. A number of key points emerged from the interviews. Characteristics of CMSI were considered unique compared to other muscle strains. Rigor in the clinical approach clarifies the diagnosis, whereas ongoing monitoring of calf capacity and responses to loading exposure provides the most accurate estimate of prognosis. Athlete intrinsic characteristics, injury factors and sport demands shaped rehabilitation across six management phases, which were guided by key principles to optimise performance at return to play (RTP) while avoiding subsequent injury or recurrence. To prevent CMSI, periodic monitoring is common, but practices vary and data are collected to inform load-management and exercise selection rather than predict future CMSI. A universal injury prevention program for CMSI may not exist. Instead, individualised strategies should reflect athlete intrinsic characteristics and sport demands. Conclusions Information provided by experts enabled a recommended approach to clinically evaluate CMSI to be outlined, highlighting the injury characteristics considered most important for diagnosis and prognosis. Principles for optimal management after CMSI were also identified, which involved a systematic approach to rehabilitation and the RTP decision. Although CMSI were reportedly difficult to prevent, on- and off-field strategies were implemented by experts to mitigate risk, particularly in susceptible athletes.
Résumé Les lésions musculaires sont fréquentes chez le sportif. Elles ont fait l’objet de plusieurs études sans toutefois aboutir à un consensus quant à leur prise en charge. Dans cet article, la discussion a été axée sur les lésions des muscles ischiojambiers (IJs) chez le footballeur, celles-ci étant les plus fréquentes. Ont été abordées les différentes étapes de cette prise en charge, du diagnostic au traitement, en passant par la prévention qui occupe une place primordiale.
New findings: What is the central question of this study? First, how does physical rehabilitation influence recovery from traumatic muscle injury? Second, how does physical activity impact the rehabilitation response for skeletal muscle function and whole-body metabolism? What is the main finding and its importance? The most salient findings are that rehabilitation impaired muscle function and range of motion; while restricting activity mitigated some negative effects but also impacted whole-body metabolism. This data suggests that first, work must continue to explore treatment parameters including modality, time, type, duration, and intensity to find the best rehabilitation approaches for volumetric muscle loss injuries. Second, restricting activity acutely might enhance rehabilitation response, but whole-body co-morbidities should continue to be considered. Abstract: Volumetric muscle loss (VML) injury occurs when a substantial volume of muscle is lost due to surgical removal or trauma resulting in an irrecoverable deficit in muscle function. Recently it was suggested that VML impacts whole-body and muscle-specific metabolism, which may contribute to the inability of the muscle to respond to treatments like physical rehabilitation. This work aimed to understand the complex relationship between physical activity and the response to rehabilitation after VML in an animal model, evaluating rehabilitation response by measurements of muscle function and whole-body metabolism. Adult male mice (n = 24) underwent a multi-muscle, full-thickness VML injury to the gastrocnemius, soleus, and plantaris muscles and were randomized into one of three groups: untreated, rehabilitation (i.e., combined electrical stimulation and range of motion; twice per week, began 72 h post-injury for ∼8 weeks), or rehabilitation and physical activity restriction. There was a lack of positive adaptions associated with electrical stimulation and range of motion intervention alone; however, maximal isometric torque of the posterior muscle group was greater in mice receiving treatment with activity restriction (p = 0.008). That said, physical activity and whole-body metabolism were measured ∼6wks post-injury; metabolic rate decreased (p = 0.001) while respiratory exchange ratio increased (p = 0.022) with activity restriction. Therefore, restricting physical activity may enhance an intervention delivered to the injured muscle group, but may impair whole-body metabolism. It is possible that restricting activity is important initially following injury to protect muscle from excess demand. Then, gradually increasing activity throughout the course of treatment may optimize muscle function and whole-body metabolism. This article is protected by copyright. All rights reserved.
Comprehensive rehabilitation requires multidisciplinary collaboration and shared decision-making to achieve the patient’s goals. Return to prior level of function may not be sufficient as a return to prior or exceeding performance is often the desired outcome. In order to achieve this, it is critical to define, assess, monitor, and train as components of an objective and criteria-based rehabilitation. A staged and periodized framework, as in strength in conditioning, can be utilized to establish a plan of care. Pragmatic clinical decision-making can be fueled by monitoring objective injury and impairment constructs such as tissue healing, mobility, strength, balance, motor control, power, conditioning, speed, agility, and quickness that are tailored to the functional level of the patient. By combining these principles within a patient-centered and evidence-based framework, rehabilitation of the ankle and foot may help establish an environment that facilitates the athlete’s desired outcome.Keywords5–8 RehabilitationPhysiotherapyExerciseFootAnkleReturn to work and sport
Plantaris tendon (PT) might induce calf or Achilles pain. In this case report, a 59-year-old woman presented with axial instability of plantaris tendon; post Achilles tendon lengthening. She beneficiated from a needle tenotomy of the PT and had a prompt symptom alleviation. The patient was fully satisfied and had a SANE score of 95% at 12 months follow up and was able to return to moderate sports activities without limitations (hiking, Nordic walking). The instability of the PT might be considered for the differential diagnosis of medial calf pain for which needle tenotomy may be considered a valuable option.
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