The single-leg heel raise does not predict maximal plantar flexion strength in healthy males and females

Physiotherapists Approach in Lateral Ankle Sprain Rehabilitation: A Survey Study

BACKGROUND

To investigate how physiotherapists approach lateral ankle sprain (LAS) rehabilitation and their rationale for exercise progression. We also sought to determine typical exercise dosage prescribed and the extent to which they rely on objective outcomes for guiding rehabilitation progression and return-to-sports decisions.

METHODS

We distributed an online survey using Qualtrics. The survey comprised a combination of 23 open and 8 closed questions to capture data on: participant demographics and clinical experience, typical caseload, LAS rehabilitation dosage, with clinical vignettes used to determine the time taken to reach key rehabilitation milestones, use of objective markers to inform rehabilitation progress, and progression to each milestone. Data were analyzed descriptively; open questions were inventoried and categorized. Proportions were then calculated per category.

RESULTS

Ninety-six physiotherapists from Belgium, the Netherlands, and the United Kingdom responded to the survey, of which 23 completed all sections. On average, less than half (46%) of the responding therapists use objective measurements to guide rehabilitation progress. The estimated time to reach key clinical milestones is equivocal among participating physiotherapists. Most physiotherapists use pain and ankle impairments (eg, range of motion and muscle strength) to guide rehabilitation progress.

CONCLUSION

This study indicates that progress in LAS rehabilitation is determined subjectively and that not the entire spectrum of impairments is assessed. Physiotherapists should implement more objective measures throughout LAS rehabilitation.

Effect of foot position during plantarflexion on the neural drive to the gastrocnemii in runners with Achilles tendinopathy

Runners with Achilles tendinopathy have reduced neural drive to the gastrocnemius lateralis. Positioning feet-inwards (feet-in) can influence gastrocnemii activity in healthy individuals. Therefore, this study investigated if pointing (feet-in) during isometric plantarflexion would increase gastrocnemius lateralis electromyography root mean square amplitude (RMS) and motor unit discharge rates (MUDR), compared to feet-neutral (feet-neutral), in Achilles tendinopathy. High-density electromyograms were recorded from gastrocnemius lateralis and medialis, during 20-s feet-in and feet-neutral contraction, in runners with (n = 18) and without (n = 19) Achilles tendinopathy. During feet-in, gastrocnemius lateralis RMS was higher in both groups and gastrocnemius medialis RMS was lower in the Achilles tendinopathy, compared to feet-neutral. MUDR were lower during feet-in in gastrocnemius lateralis (p < 0.001) and in gastrocnemius medialis in the Achilles tendinopathy group. The Achilles tendinopathy group had lower triceps surae endurance during single leg heel raise. In summary, feet-in increases gastrocnemius lateralis RMS in both groups, conversely reducing MUDR in the Achilles tendinopathy group, compared to feet-neutral. Additionally, feet-in reduces gastrocnemius medialis RMS and MUDR only in the Achilles tendinopathy group, compared to feet-neutral. This would shift the gastrocnemius lateralis/medialis ratio excitation, favouring gastrocnemius lateralis. Nonetheless, while this strategy holds promise, it remains uncertain whether performing plantarflexion exercise with feet pointed inwards would provide additional benefits for the treatment of runners with Achilles tendinopathy. Our findings suggest that the increased gastrocnemius lateralis RMS during feet-in may not be as consequence of increased MUDR and, but it might be a result of recruitment of more motor units.

Smartphone Assessment of the Sitting Heel-Rise Test

The study presents a new approach for assessing plantarflexor muscles' function using a smartphone. The test involves performing repeated heel raises for 60 s while seated. The seated heel-rise test offers a simple method for assessing plantarflexor muscles' function in those with severe balance impairment who are unable to complete tests performed while standing. The study aimed to showcase how gyroscopic data from a smartphone placed on the lower limb can be used to assess the test. Eight participants performed the seated heel-rise test with each limb. Gyroscope and 2D video analysis data (60 Hz) of limb motion were used to determine the number of cycles, the average rise (T-rise), lowering (T-lower), and cycle (T-total) times. The number of cycles detected matched exactly when the gyroscope and kinematic data were compared. There was good time domain agreement between gyroscopic and video data (T-rise = 0.0005 s, T-lower = 0.0013 s, and T-total = 0.0017 s). The 95% CI limits of agreement were small (T-total -0.1118, 0.1127 s, T-lower -0.1152, 0.1179 s, and T-total -0.0763, 0.0797 s). Results indicate that a smartphone placed on the thigh can successfully assess the seated heel-rise test. The seated heel-rise test offers an attractive alternative to test plantarflexor muscles' functionality in those unable to perform tests in standing positions.

A randomised crossover trial on the effects of foot starting position on calf raise test outcomes: Position does matter

BACKGROUND

This randomised crossover study with repeated measures examined the influence of the three most common foot starting positions used in conducting the calf raise test (CRT) on test outcomes. This study also accounted for the potential influence of gender, age, body mass index (BMI), and level of physical activity on test outcomes.

METHODS

Forty-nine healthy individuals (59 % female, 21 ± 4 years) performed single-leg calf raise repetitions in a human movement laboratory in three randomised foot starting positions: flat, 10° incline, and step. The validated Calf Raise application was used to track the vertical displacement of a marker placed on the foot using computer vision. The application extracted the following CRT outcomes from the vertical displacement curve: number of repetitions, peak vertical height, total vertical displacement, and total positive work. Data were analysed using mixed-effects models and stepwise regression.

RESULTS

There was a significant main effect (P < 0.001) of foot starting position on all outcomes, with all paired comparisons being statistically significant (P ≤ 0.023). Repetitions, total vertical displacement, and total positive work were greatest in flat and lowest in step, whereas peak vertical height was greatest in incline and lowest in step. Gender (P = 0.021; males>females) and BMI (P = 0.002; lower BMI>higher BMI) significantly influenced the number of repetitions. Gender (P < 0.001; males>females) also influenced total positive work. Age and physical activity levels did not significantly influence CRT outcomes.

CONCLUSIONS

CRT foot starting position mattered and significantly affected all CRT outcomes. CRT foot starting position needs consideration when contrasting data in research and practice.

Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study

BACKGROUND

A number of studies have reported that calf muscle atrophy is a common long-term problem after Achilles tendon repair; however, there is still a lack of data concerning early postoperative morphological changes in the calf muscle after surgery.

PURPOSE

To investigate changes over time in calf muscle volume and fatty degeneration during 1 year after Achilles tendon repair.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective 1-year serial magnetic resonance imaging study was carried out with 20 patients who underwent tendon repair for unilateral acute Achilles tendon rupture. The magnetic resonance imaging assessment in addition to clinical and functional evaluations was performed at 1, 3, 6, and 12 months after surgery. The muscle volume of the medial and lateral gastrocnemius, soleus, and flexor hallucis longus (FHL) and fatty degeneration of the medial and lateral gastrocnemius and soleus were measured for the calf muscles, and the relative volume and fatty degeneration changes in the affected leg compared with the healthy contralateral leg were calculated as a percentage ([injured/healthy control] × 100) to assess structural changes over time.

RESULTS

Muscle volumes of the medial gastrocnemius, lateral gastrocnemius, soleus, and FHL were 92.3%, 92.8%, 84.6%, and 95.9% at 12 months after surgery, respectively. Medial and lateral gastrocnemius and FHL muscle volumes improved over time and recovered to almost equal to that of the healthy side at 12 months after surgery. The soleus muscle volume did not recover significantly over time and was statistically significantly smaller than that of the healthy side at 12 months (P = .029). Fatty degeneration rates of the medial gastrocnemius, lateral gastrocnemius, and soleus were 118.2%, 113.9% and 121.1% at 12 months after surgery, respectively. Fatty degeneration of the medial and lateral gastrocnemius did not change significantly, but there was a statistically significant increase in fatty degeneration of the soleus over time (P < .001).

CONCLUSION

Within the triceps surae muscle, the soleus was the most negatively affected by injury and repair for both muscle volume and fatty degeneration. Postoperative management to recover the soleus muscle function before a return to sporting activities should be considered in the future.

Plantar Flexor Weakness and Pain Sensitivity Cannot Be Assumed in Midportion Achilles Tendinopathy

Introduction/Purpose

The purpose of this study was to determine the following in persons with midportion Achilles tendinopathy (AT): 1) maximal strength and power; 2) neural drive during maximal contractions and contractile function during electrically evoked resting contractions; and 3) whether pain, neural drive, and contractile mechanisms contribute to differences in maximal strength.

Methods

Twenty-eight volunteers (14 AT, 14 controls) completed isometric, concentric, and eccentric maximal voluntary contractions (MVCs) of the plantar flexors in a Biodex™ dynamometer. Supramaximal electrical stimulation of the tibial nerve was performed to quantify neural drive and contractile properties of the plantar flexors. Pain sensitivity was quantified as the pressure-pain thresholds of the Achilles tendon, medial gastrocnemius, and upper trapezius.

Results

There were no differences in plantar flexion strength or power between AT and controls (isometric MVC: P = 0.95; dynamic MVC: P = 0.99; power: P = 0.98), nor were there differences in neural drive and contractile function (P = 0.55 and P = 0.06, respectively). However, the mechanisms predicting maximal strength differed between groups: neural drive predicted maximal strength in controls (P = 0.02) and contractile function predicted maximal strength in AT (P = 0.001). Although pain did not mediate these relationships (i.e., between maximal strength and its contributing mechanisms), pressure-pain thresholds at the upper trapezius were higher in AT (P = 0.02), despite being similar at the calf (P = 0.24) and Achilles tendon (P = 0.40).

Conclusions

There were no deficits in plantar flexion strength or power in persons with AT, whether evaluated isometrically, concentrically, or eccentrically. However, the mechanisms predicting maximal plantar flexor strength differed between groups, and systemic pain sensitivity was diminished in AT.

Devices to measure calf raise test outcomes: A narrative review

BACKGROUND

The calf raise test (CRT) is commonly administered without a device in clinics to measure triceps surae muscle function. To standardise and objectively quantify outcomes, researchers use research-grade or customised CRT devices. To incorporate evidence-based practice and apply testing devices effectively in clinics, it is essential to understand their design, applicability, psychometric properties, strengths, and limitations. Therefore, this review identifies, summarises, and critically appraises the CRT devices used in science.

METHODS

Four electronic databases were searched in April 2022. Studies that used devices to measure unilateral CRT outcomes (i.e., number of repetitions, work, height) were included.

RESULTS

Thirty-five studies met inclusion, from which seven CRT devices were identified. Linear encoder (n = 18) was the most commonly used device, followed by laboratory equipment (n = 6) (three-dimensional motion capture and force plate). These measured the three CRT outcomes. Other devices used were electrogoniometer, Häggmark and Liedberg light beam device, Ankle Measure for Endurance and Strength (AMES), Haberometer, and custom-made. Devices were mostly used in healthy populations or Achilles tendon pathologies. AMES, Haberometer, and custom-made devices were the most clinician-friendly, but only quantified repetitions were completed. In late 2022, a computer vision mobile application appeared in the literature and offered clinicians a low-cost, research-grade alternative.

CONCLUSION

This review details seven devices used to measure CRT outcomes. The linear encoder is the most common in research and quantifies all three CRT outcomes. Recent advances in computer-vision provide a low-cost research-grade alternative to clinicians and researchers via a n iOS mobile application.

Narrative Review of Sex Differences in Muscle Strength, Endurance, Activation, Size, Fiber Type, and Strength Training Participation Rates, Preferences, Motivations, Injuries, and Neuromuscular Adaptations

ABSTRACT

Nuzzo, JL. Narrative review of sex differences in muscle strength, endurance, activation, size, fiber type, and strength training participation rates, preferences, motivations, injuries, and neuromuscular adaptations. J Strength Cond Res 37(2): 494-536, 2023-Biological sex and its relation with exercise participation and sports performance continue to be discussed. Here, the purpose was to inform such discussions by summarizing the literature on sex differences in numerous strength training-related variables and outcomes-muscle strength and endurance, muscle mass and size, muscle fiber type, muscle twitch forces, and voluntary activation; strength training participation rates, motivations, preferences, and practices; and injuries and changes in muscle size and strength with strength training. Male subjects become notably stronger than female subjects around age 15 years. In adults, sex differences in strength are more pronounced in upper-body than lower-body muscles and in concentric than eccentric contractions. Greater male than female strength is not because of higher voluntary activation but to greater muscle mass and type II fiber areas. Men participate in strength training more frequently than women. Men are motivated more by challenge, competition, social recognition, and a desire to increase muscle size and strength. Men also have greater preference for competitive, high-intensity, and upper-body exercise. Women are motivated more by improved attractiveness, muscle "toning," and body mass management. Women have greater preference for supervised and lower-body exercise. Intrasexual competition, mate selection, and the drive for muscularity are likely fundamental causes of exercise behaviors in men and women. Men and women increase muscle size and strength after weeks of strength training, but women experience greater relative strength improvements depending on age and muscle group. Men exhibit higher strength training injury rates. No sex difference exists in strength loss and muscle soreness after muscle-damaging exercise.

The heel-raise test for ankle plantarflexor strength: a scoping review and meta-analysis of studies providing norms

[Purpose] The heel-raise test (HRT) is sometimes used to quantify ankle plantarflexion strength. However, descriptions of the test vary and normative values are limited. This paper, therefore was generated to summarize procedures and provide normative values for the HRT in a younger and older age group of adults. [Methods] Electronic and hand searches were conducted to identify relevant literature. Meta-analysis was used to provide norms. [Results] Among 439 nonduplicative articles identified, 13 qualifying articles were ultimately included. Procedures for the HRT described in the studies varied considerably. The mean number of HRT repetitions was 28.7 for adults with a mean age less than 40 years and 11.8 for adults with a mean age greater than 60 years. [Conclusion] This study provides information on HRT performance and norms derived with them for younger and older adults.