Accuracy of Prediction Equations to Calculate Maximum Strength

Accuracy of a New Prediction Equation to Calculate One Repetition Maximum (1RM) in Trained and Untrained Young and Old Adults

Resistance exercise training (RT) is a key component of health related exercise programs. However, an accurate specification of RT load prescription is essential for effective and safe achievement of training aims. Proper specification of exercise intensity might be the most critical issue when designing RT protocols for adults. One repetition maximum tests (1RM) have been considered the "gold standard" of dynamic maximum strength evaluation. Although the argument of increased risk of injuries and adverse effects with 1RM testing in older people has been rejected by several studies , limited motivation to lift maximum loads, requirement for high test effort, time constraints, and interruption of the continuity of the training process aggravate the frequent application of 1RM tests particularly in non-athletic RT. 1RM prediction equations that use the load and number of repetitions completed to fatigue (RTF) to predict repetition maximum might be a reliable and feasible option to 1RM testing. Thus, the primary aims of this study were to evaluate the predictive accuracy of current RTF equations and to develop an equation that more accurately predicts 1RM from RTF tests.

Study Overview

• Status: Enrolling by invitation
• Conditions: Healthy Aging
• Intervention / Treatment: Other: resistance exercise tests

• Study Type: Observational
• Enrollment (Estimated): 120

Contacts and Locations

Study Locations

• Germany
  • Erlangen, Germany, 91054
    • Institute of Radiology, University Hospital NErlangen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of resistance trained and untrained women and men 18 to 35 or 60-85 years old that are able to complete 1RM and RTF tests without endangering their health

Description

Inclusion Criteria:

• 18 to 35 years old
• 60 to 85 years old

Exclusion Criteria:

• Contraindication for one repetition maximum tests
• musculoskeletal injuries that may prevent a reliable and safe assessment of the 1RM and RTF tests

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum load, one repetition maximum, leg press	Maximum load lifted once (1RM, in kg) for the leg press exercise	At baseline - no follow up tests

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum load lifted at 5-8RM, leg press	Maximum load lifted 5-8 times (RFT5-8, in kg) for the leg press exercise	At baseline - no follow up tests
Maximum load lifted at 9-12RM, leg press	Maximum load lifted 5-8 times (RFT9-12, in kg) for the leg press exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, leg press	Maximum load lifted 5-8 times (RFT13-16, in kg) for the leg press exercise	At baseline - no follow up tests
Maximum load, one repetition maximum, lat pulls	Maximum load lifted once (1RM, in kg) for the latissimus pull exercise	At baseline - no follow up tests
Maximum load lifted at 5-8 RM, lat pulls	Maximum load lifted 5-8 times (RFT5-8, in kg) for the latissimus pull exercise	At baseline - no follow up tests
Maximum load lifted at 9-12 RM, lat pulls	Maximum load lifted 9-12 times (RFT9-12, in kg) for the latissimus pull exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, lat pulls	Maximum load lifted 13-16 times (RFT13-16, in kg) for the latissimus pull exercise	At baseline - no follow up tests
Maximum load, one repetition maximum, triceps dips	Maximum load lifted once (1RM, in kg) for the triceps dips exercise	At baseline - no follow up tests
Maximum load lifted at 5-8 RM, triceps dips	Maximum load lifted 5-8 times (RFT5-8, in kg) for the triceps dips exercise	At baseline - no follow up tests
Maximum load lifted at 9-12 RM, triceps dips	Maximum load lifted 9-12 times (RFT9-12, in kg) for the triceps dips exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, triceps dips	Maximum load lifted 13-16 times (RFT13-16, in kg) for the triceps dips exercise	At baseline - no follow up tests
Maximum load, one repetition maximum, trunk extension	Maximum load lifted once (1RM, in kg) for the trunk extension exercise	At baseline - no follow up tests
Maximum load lifted at 5-8 RM, trunk extension	Maximum load lifted 5-8 times (RFT5-8, in kg) for the trunk extension exercise	At baseline - no follow up tests
Maximum load lifted at 9-12 RM, trunk extension	Maximum load lifted 9-12 times (RFT9-12, in kg) for the trunk extension exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, trunk extension	Maximum load lifted 13-16 times (RFT13-16, in kg) for the trunk extension exercise	At baseline - no follow up tests
Maximum load, one repetition maximum, trunk flexion	Maximum load lifted once (1RM, in kg) for the trunk flexion exercise	At baseline - no follow up tests
Maximum load lifted at 5-8 RM, trunk flexion	Maximum load lifted 5-8 times (RFT5-8, in kg) for the trunk flexion exercise	At baseline - no follow up tests
Maximum load lifted at 9-12 RM, trunk flexion	Maximum load lifted 9-12 times (RFT9-12, in kg) for the trunk flexion exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, trunk flexion	Maximum load lifted 13-16 times (RFT13-16, in kg) for the trunk flexion exercise	At baseline - no follow up tests
Maximum load, one repetition maximum, leg flexion	Maximum load lifted once (1RM, in kg) for the leg flexion exercise	At baseline - no follow up tests
Maximum load lifted at 5-8 RM, leg flexion	Maximum load lifted 5-8 times (RFT5-8, in kg) for the leg flexion exercise	At baseline - no follow up tests
Maximum load lifted at 9-12 RM, leg flexion	Maximum load lifted 9-12 times (RFT9-12, in kg) for the leg flexion exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, leg flexion	Maximum load lifted 13-16 times (RFT13-16, in kg) for the leg flexion exercise	At baseline - no follow up tests
Maximum load, one repetition maximum, leg extension	Maximum load lifted once (1RM, in kg) for the leg extension exercise	At baseline - no follow up tests
Maximum load lifted at 5-8 RM, leg extension	Maximum load lifted 5-8 times (RFT5-8, in kg) for the leg extension exercise	At baseline - no follow up tests
Maximum load lifted at 9-12 RM, leg extension	Maximum load lifted 9-12 times (RFT9-12, in kg) for the leg extension exercise	At baseline - no follow up tests
Maximum load lifted at 13-16 RM, leg extension	Maximum load lifted 13-16 times (RFT13-16, in kg) for the leg extension exercise	At baseline - no follow up tests

Collaborators and Investigators

• Sponsor: University of Erlangen-Nürnberg Medical School

Study record dates

Study Major Dates

• Study Start (Actual): December 2, 2024
• Primary Completion (Estimated): August 31, 2026
• Study Completion (Estimated): September 30, 2026

Study Registration Dates

• First Submitted: December 1, 2024
• First Submitted That Met QC Criteria: December 4, 2024
• First Posted (Actual): December 5, 2024

Study Record Updates

• Last Update Posted (Actual): January 29, 2026
• Last Update Submitted That Met QC Criteria: January 28, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: resistance exercise; maximum strength; one repetition maximum; repetitions to fatigue; prediction equation
• Other Study ID Numbers: PREDEQ; Physiomed ID 101 (Other Identifier: UKER - FAU)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No