<![CDATA[ABSTRACT Physical condition is one of the main factors determining volleyball players’ performance because this sport requires athletes to move quickly, change direction accurately, and perform explosive jumps during both offensive and defensive situations. However, physical training programs at the local club level still tend to emphasize general exercises, resulting in less optimal improvement in agility and leg muscle power. This study aimed to analyze the effect of High Intensity Interval Training (HIIT) on agility and leg muscle power among volleyball players of Club Family Suela. The study employed a quantitative approach using a quasi-experimental method with a one group pretest-posttest design. The sample consisted of 14 active players selected through purposive sampling from a population of 20 athletes. The HIIT program was conducted for six weeks with a training frequency of three sessions per week. Agility was measured using the Illinois Agility Test, while leg muscle power was assessed through the Vertical Jump Test. Data were analyzed using descriptive statistics, the Shapiro-Wilk normality test, and the paired sample t-test. The results showed an improvement in physical performance after the intervention, indicated by a decrease in agility time from 18.31 seconds to 16.21 seconds and an increase in average vertical jump performance from 56.21 cm to 58.50 cm. Statistical analysis revealed a significance value of p < 0.001, indicating that HIIT had a significant effect on improving agility and leg muscle power. These findings suggest that HIIT can be used as an effective and efficient alternative physical training method to support volleyball players’ performance. ABSTRAK Kondisi fisik menjadi salah satu faktor utama yang menentukan performa pemain bola voli karena olahraga ini menuntut kemampuan bergerak cepat, melakukan perubahan arah secara tepat, dan menghasilkan lompatan eksplosif saat menyerang maupun bertahan. Namun, pembinaan fisik pemain pada tingkat klub lokal masih sering berfokus pada latihan umum sehingga peningkatan kelincahan dan power otot tungkai belum optimal. Penelitian ini bertujuan untuk menganalisis pengaruh latihan High Intensity Interval Training (HIIT) terhadap kelincahan dan power otot tungkai pemain bola voli Club Family Suela. Penelitian menggunakan pendekatan kuantitatif dengan metode eksperimen semu melalui desain one group pretest-posttest. Sampel penelitian terdiri atas 14 pemain aktif yang dipilih menggunakan teknik purposive sampling dari total populasi 20 pemain. Program HIIT dilaksanakan selama enam minggu dengan frekuensi latihan tiga kali setiap minggu. Pengukuran kelincahan dilakukan menggunakan Illinois Agility Test, sedangkan power otot tungkai diukur melalui Vertical Jump Test. Data dianalisis menggunakan statistik deskriptif, uji normalitas Shapiro-Wilk, dan paired sample t-test. Hasil penelitian menunjukkan adanya peningkatan kemampuan fisik setelah perlakuan, ditandai dengan penurunan rata-rata waktu kelincahan dari 18,31 detik menjadi 16,21 detik serta peningkatan rata-rata vertical jump dari 56,21 cm menjadi 58,50 cm. Hasil uji statistik menunjukkan nilai signifikansi p < 0,001 sehingga latihan HIIT terbukti berpengaruh signifikan terhadap peningkatan kelincahan dan power otot tungkai. Temuan ini menunjukkan bahwa HIIT dapat digunakan sebagai alternatif metode latihan fisik yang efektif dan efisien dalam mendukung performa pemain bola voli.]]>
