Effects of Resistance Training on Women With Functional Hypothalamic Amenorrhea

Number of participants in the Functional Hypothalamic Amenorrhea (FHA) group who experience at least one spontaneous menstrual bleeding episode during the 8-week intervention. Menstrual status is monitored daily using non-invasive methods: self-reported menstrual diaries and basal body temperature (BBT) tracking with a digital thermometer (SENTI2) to identify hormonal fluctuations. Recovery is defined as the occurrence of the first menses post-intervention commencement.

Evaluation of lower-limb power through the Countermovement Jump (CMJ) test performed on a force platform. Jump height (cm) and power output (W/kg) were recorded to assess neuromuscular adaptations.

Evaluation of upper-limb strength through handgrip dynamometry testing. Grip strength (kg) was recorded to assess changes in maximal upper-limb force production.

Evaluation of body mass using bioelectrical impedance analysis. Body mass (kg) will be assessed before and after the intervention to monitor changes associated with menstrual recovery and the exercise intervention.

Evaluation of fat mass using bioelectrical impedance analysis. Fat mass (%) will be assessed before and after the intervention to determine body composition changes during menstrual recovery.

Body mass index (BMI, kg/m²) will be calculated from body mass and height measurements to evaluate anthropometric changes following the intervention.

Assessment of psychological well-being using the Short Form-36 (SF-36) questionnaire. This tool evaluates eight health domains, with total scores ranging from 0 to 100; higher scores indicate better health status and quality of life.

A 19-item questionnaire generating seven component scores and one global score used to assess sleep quality. The global PSQI score ranges from 0 to 21 points, with higher scores reflecting poorer sleep quality. A global score >5 indicates poor sleep quality.

The Low Energy Availability in Females Questionnaire (LEAF-Q) is a 25-item instrument designed to assess risk factors associated with low energy availability in physically active females, including menstrual function, gastrointestinal symptoms, and injury history. The questionnaire provides a total score ranging from 0 to 25 points, with higher scores indicating greater risk of low energy availability and related conditions. A total score ≥8 is considered indicative of increased risk for low energy availability and the Female Athlete Triad/Relative Energy Deficiency in Sport (RED-S).

The Eating Attitudes Test-26 (EAT-26) is a 26-item questionnaire assessing symptoms and concerns characteristic of eating disorders. It provides a total score and three subscales: dieting, bulimia and food preoccupation, and oral control. Total scores range from 0 to 78 points, with higher scores indicating greater disordered eating symptomatology. A total score ≥20 suggests potentially problematic eating behaviors and risk of eating disorders.

The Menstrual Distress Questionnaire (MDQ) is a 22-item Likert-scale questionnaire designed to assess physical, psychological, and behavioral symptoms associated with the menstrual cycle. The questionnaire provides a total score ranging from 22 to 110 points, with higher scores indicating greater menstrual-related distress and symptom severity.

Assessment of heart rate variability (HRV) through the root mean square of successive differences between adjacent R-R intervals recorded via a heart rate monitor at rest.The following variables were obtained: mean R-R interval (RR, ms) and the root mean square of successive differences between adjacent R-R intervals (RMSSD, ms), to assess autonomic nervous system activity and cardiac autonomic modulation.